这题怎么判断decision price的？

NO.PZ202110280100000104 问题如下 The implementation shortfall, in basis points (bps), for the sell orr of West Commershares is closest to: A.139. B.198. C.206. Execution cost = [(–6,000 × 26.80) + (–3,000 × 26.30)] – (–9,000 × 27.10) = 4,200.Opportunity cost = [–10,000 – (–9,000)] × (26.00 – 27.10) = 1,100.Fees = 9,000 × 0.03 = 270.So, the implementation shortfall ($) is calculateasImplementation shortfall ($) = 4,200 + 1,100 + 270 = 5,570.Finally, the implementation shortfall (bps) is calculate 基础班的ppt好像没有implementation shortfall（bps）的公式？

NO.PZ202110280100000104 问题如下 The implementation shortfall, in basis points (bps), for the sell orr of West Commershares is closest to: A.139. B.198. C.206. Execution cost = [(–6,000 × 26.80) + (–3,000 × 26.30)] – (–9,000 × 27.10) = 4,200.Opportunity cost = [–10,000 – (–9,000)] × (26.00 – 27.10) = 1,100.Fees = 9,000 × 0.03 = 270.So, the implementation shortfall ($) is calculateasImplementation shortfall ($) = 4,200 + 1,100 + 270 = 5,570.Finally, the implementation shortfall (bps) is calculate cision price如何确定？不是有个limit pri26.2吗？麻烦老师帮忙解答。

NO.PZ202110280100000104 问题如下 The implementation shortfall, in basis points (bps), for the sell orr of West Commershares is closest to: A.139. B.198. C.206. Execution cost = [(–6,000 × 26.80) + (–3,000 × 26.30)] – (–9,000 × 27.10) = 4,200.Opportunity cost = [–10,000 – (–9,000)] × (26.00 – 27.10) = 1,100.Fees = 9,000 × 0.03 = 270.So, the implementation shortfall ($) is calculateasImplementation shortfall ($) = 4,200 + 1,100 + 270 = 5,570.Finally, the implementation shortfall (bps) is calculate 老师帮我看看我的计算哪里有问题（27.1-26）*10000-【0.3*6000+0.8*3000-0.03*9000]