问题如下：
Devin, Egbert, and Humphrey, financial analysts from the same investment firm, gave the following personal insights on sector indices:
Devin:Sector indices track different economic sectors and cannot be aggregated to represent the equivalent of a broad market index.
Egbert:Sector indices provide a means to determine whether an active investment manager is more successful at stock selection or sector allocation.
Humphrey:Sector indices apply a universally agreed upon sector classification system to identify the constituent securities of specific economic sectors, such as consumer goods, energy, finance, health care.
Whose statement is most correct?
选项：
A.Devin.
B.Egbert.
C.Humphrey.
解释：
The Sector Index provides a way to determine whether an active investment manager is more successful at stock selection or sector allocation.
老师您好，我想知道为什么行业指数会是一种能决定为什么一个主动投资经理在股票选择上更成功还是在行业综合上更成功
