这题不太理解在考什么？可以解答下吗

问题如下：

According to the CFA Institute Code of Ethics and Standards of Professional Conduct, trading on material nonpublic information is least likely to be prevented by establishing:

选项：

A.personal trading limitations. B.selective disclosure. C.firewalls.

解释：

Selective disclosure occurs when companies discriminate in making material nonpublic information public. Corporations that disclose information on a limited basis create the potential for insider-trading violations. See Standard II(A)