答案B是哪儿错了呢？

问题如下：

What is the key element in fostering a culture of ethical decision-making within the employees of an investment firm?

选项：

A.Establishing a robust integrity culture led by senior management.

B.Implementing a detailed code of ethics that outlines the firm’s moral guidelines.

C.Relying on the innate ethical inclinations of the investment professionals.

解释：

A Correct. The most crucial aspect in nurturing ethical behavior in an investment firm is the creation and upkeep of a strong integrity culture, primarily led and exemplified by the firm's senior management. While a code of ethics and individual ethical inclinations are significant, they do not surpass the impact of leadership's commitment to integrity.