2020年mock 上午题 equity的B题，我是从这两个角度回答的，老师看看逻辑对吗？
（1）从降低相关性角度：投资不同sector，Invest in different industry that has low correlation, can achieve a lower variance and better diversification benefit.
（2）增加security数量 Invest more securities, increase the number of security can reduce the active risk, like follow the index.
