问题如下：
Which of the following statements about portfolio method is correct?
选项：
A.Investors should use a portfolio approach to reduce the overall volatility of returns.
B.Investors should use a portfolio approach to monitor overall volatility of returns.
C.Investors should use a portfolio approach to eliminate the overall volatility of returns.
解释：
A is correct.
The volatility of the portfolio can be reduced by combining assets . Holding porfolios can help individuals and institutions to reduce risk. However, because of the impact of economic change during a period, the risk may not reduce as much as expected.
B为什么错了呢
