文中提到了书面修改ips，不能剔除吗？

问题如下：

The core-plus fixed-income composite includes a portfolio managed on behalf of the Bida Academy endowment fund. The trustees of Bida inform Bamako in writing that because of a change in investment policy, the endowment fund is no longer permitted to hold below-investment- grade securities. Bamako determines that henceforth, the Bida portfolio should be included in the core fixed-income composite rather than the core-plus fixed-income composite. The historical record of the portfolio must be:

选项：

included in both composites.

kept in the core-plus fixed-income composite.

excluded from the core-plus fixed-income composite.

解释：

B is correct.

The portfolio’s historical performance must remain with the original composite. Portfolios must not be switched from one composite to another unless either documented changes to a portfolio’s investment mandate, objective, or strategy or the redefinition of the composite make it appropriate.

投资组合的历史表现必须与原始composite保持一致。 投资组合不得从一种composite转换为另一种composite，除非对组合的投资授权、目标或策略进行了记录在案的更改，或者composite的重新定义使其适当。