问题如下：
If the portfolio is not fully diversified, which of the following is most suitable permormance measures?
选项：
A. M-squared.
B. Treynor ratio.
C. Jensen’s alpha.
解释：
A is the correct.
When a portfolio is not fully diversified, the appropriate performance measures should be M-squared which is based on total risk.
C为啥不可以呢？？？
