NO.PZ2018070201000051
问题如下：
A risk-free asset will produce a numerical utility that is:
选项：
A.equal for all kinds of investors.
B.negative for risk-averse investors.
C.zero for risk seeking investors.
解释：
A is correct.
The utility of a risk-free asset is the same for all the investor types as it has a variance of zero.
题目直接翻译是什么时候效用是数字， 效用无论是否变化，是否等于E(R) 都是数字呀。
看其他题解析这题是在问 deviation =0 的时候
