Total risk versus total variance

Hi guys,
To me both statements below are correct, but it seems that B is incorrect. I can’t understand why, can someone please help?

A- The sum of an asset’s systematic variance and its nonsystematic variance of returns is equal to the asset’s total variance.
B- The sum of an asset’s systematic standard deviation and its nonsystematic standard deviation of returns is equal to the asset’s total risk

Variances add; standard deviations don’t.