这题不是很理解，请解释说明下

NO.PZ2022120703000089 问题如下 Whiof the following ESG strategies is least likely useprivate equity firms? A.Positive screening B.Thematic investing C.Negative screening C is correbecause \"like other investor types, private equity investors mcertainly impose exclusionary screening i.e. negative screening on any number of criteria to restriinvestment in certain sectors, either normatively or ethically fine However, private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteriHowever, portfolio managers cbenchmark segments of the portfolio against smaller investment universes, even inclung public companies, if ta comparability exists. Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter\"; anleast likely ththey wouluse negative screening.A is incorrebecause \"private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteria … Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter.\"B is incorrebecause \"private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteria … Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter.\" 如果最不可能采用negative screening, 是因为PE投资缺乏数据披露，透明度等等，那么同样需要采用数据披露的possitive screening 同样也没办法采用啊？如果说会采用正面筛选，选择ESG表现好的公司去投，披露不足的情况下，谁知道你做得好不好呢，同理，也不知道你做得不好。所以对于PE来说，不知道C和A的最本质区别到底在哪里

NO.PZ2022120703000089 问题如下 Whiof the following ESG strategies is least likely useprivate equity firms? A.Positive screening B.Thematic investing C.Negative screening C is correbecause \"like other investor types, private equity investors mcertainly impose exclusionary screening i.e. negative screening on any number of criteria to restriinvestment in certain sectors, either normatively or ethically fine However, private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteriHowever, portfolio managers cbenchmark segments of the portfolio against smaller investment universes, even inclung public companies, if ta comparability exists. Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter\"; anleast likely ththey wouluse negative screening.A is incorrebecause \"private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteria … Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter.\"B is incorrebecause \"private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteria … Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter.\" 感觉A和C的非常牵强。A为什么“并不妨碍”，可以举例子吗？C排除性筛选时，为什么一定要用指数和基数，排除性筛选的时候，本身就很大程度上是基于道德或信仰。对于某公司或行业，虽然缺少信息披露，但是就是直接排除呀。否则，那不就是反向的积极筛选。请举例子。

NO.PZ2022120703000089问题如下 Whiof the following ESG strategies is least likely useprivate equity firms? A.Positive screeningB.Thematic investingC.Negative screening C is correbecause \"like other investor types, private equity investors mcertainly impose exclusionary screening i.e. negative screening on any number of criteria to restriinvestment in certain sectors, either normatively or ethically fine However, private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteriHowever, portfolio managers cbenchmark segments of the portfolio against smaller investment universes, even inclung public companies, if ta comparability exists. Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter\"; anleast likely ththey wouluse negative screening.A is incorrebecause \"private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteria … Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter.\"B is incorrebecause \"private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteria … Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter.\" 另外，怎么区分positive screening和negative的呢？

NO.PZ2022120703000089问题如下 Whiof the following ESG strategies is least likely useprivate equity firms? A.Positive screeningB.Thematic investingC.Negative screening C is correbecause \"like other investor types, private equity investors mcertainly impose exclusionary screening i.e. negative screening on any number of criteria to restriinvestment in certain sectors, either normatively or ethically fine However, private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteriHowever, portfolio managers cbenchmark segments of the portfolio against smaller investment universes, even inclung public companies, if ta comparability exists. Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter\"; anleast likely ththey wouluse negative screening.A is incorrebecause \"private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteria … Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter.\"B is incorrebecause \"private equity investors not have the benefit of the breah anversity of inces anbenchmarks of the listeequities space, limiting opportunities for peer comparability analysis or portfolio optimization efforts arounESG criteria … Hence, it is more likely ththe GPs mapply some form of positive screening or thematic focus within their respective investment charter.\" 本题为什么不能选A？未上市股票公司为什么不能用负面筛选投资策略？