问题如下图：老师你好，可以解释下答案最后一句话，也就是B选项，谢谢
选项：
A. 
B. 
C. 
解释：
NO.PZ2018070201000088问题如下Whiof the following statements is correct?A.The beta of asset is equto the sum of asset’s systematic variananits nonsystematic varianof returns.B.The totrisk of asset is equto the sum of asset’s systematic variananits nonsystematic varianof returns.C.The totvarianof asset is equto the sum of asset’s systematic variananits nonsystematic varianof returns.C is correct.The asset's totvarianis equto the sum of systematic varianannonsystematic variance. References to totrisk the sum of systematic risk annonsystematic risk refer to variance, not to risk.请问有公式支持这个结论吗？
NO.PZ2018070201000088 可以一下题吗，然后知识点在课件哪页？哪个视频几分几秒？
为什么B不对呢？风险不就是用方差衡量的吗
