问题如下：
Address the following questions about the information ratio.
A. What is the information ratio of an index fund that effectively meets its investment objective?
B. What are the two types of risk an active investment manager can assume in seeking to increase his information ratio?
选项：
解释：
A. An index fund that effectively meets its investment objective is expected to have an information ratio of zero, because its active return should be zero.
B. The active manager may assume active factor risk and active specific risk (security selection risk) in seeking a higher information ratio.
既然是index fund，是不是意味着即使能在active为0的情况下有创造active return的机会，这个fund也不要这部分active return？所以active return应该是0，才说明meet了index fund的投资目的？
