问题如下：
Listed below are some statements about the risk of an equity security, which is incorrect?
选项：
A.The risk of an equity security is based on the uncertainty of its cash flows.
B.The risk of an equity security is based on the uncertainty of its future price.
C.The risk of an equity security is measured using the standard deviation of its dividends.
解释：
C is correct.
Not all equity securities pay dividends, so standard deviation of dividend is not suitable to measure the risk of all stock securities.
老师 那些stock不适合用deviation去衡量risk
