NO.PZ2019012201000010
问题如下：
Which of following is not one of initial requirements for an index to become the basis for an equity investment strategy?
选项：
A.Rules-based.
B.Transparent.
C.Cost-benefit.
解释：
C is correct.
考点：Indexes as a Basis for Investment
解析：指数要成为股票投资策略的基础，必须满足三个前提条件。它必须是基于规则的、透明的以及可投资的。成本效益不属于三个前提条件之一。
请问下cost benefit是什么意思
