請問可以解說為什麼A是錯誤？

问题如下：

One of the largest global investment firms holds US$1.5 trillion in AUM in over 400 actively managed mutual funds. One of the most challenging aspects of successful engagement with the investees is:

选项：

A.hiring external stewardship services.

B.resource constraints within the investment firm.

C.finding other asset managers to share the concerns regarding the individual investees.

解释：

B is correct. Having enough resources (time, expertise, leverage) for large asset managers to engage effectively with investee companies is a significant challenge. Firm resources are also critical in hiring external stewardship services or in engaging with other asset managers in approaching investees on problems identified.