问题如下：
A firm specialized in managing fixed income portfolios decides to hire a sub-advisor to manage equities. For periods beginning on or after 1 January 2006, the firm must:
选项：
A.disclose the use of a sub-advisor and the investment strategies used.
B.disclose the use of a sub-advisor and the periods a sub-advisor was used.
C.not hire such sub-advisor.
解释：
B is correct.
考点：条款4.A.25
解析：条款4.A.25 For periods beginning on or after 1 January 2006, firms must disclose the use of a subadvisor and the periods a sub-advisor was used. 自2006年1月1日起，公司必须披露雇佣的副顾问以及其被雇佣的时间。
investment strategies used就不用披露了吗？
