Regarding Time-Series Second Moments of Periodic Investment Returns Data, Relevant

Regarding time-series second moments of periodic investment returns data, relevant to portfolio investment analysis:

A) An asset's own return variance measures the asset's total risk and its covariance with a portfolio measures its potential contribution to the risk in that portfolio.
B) An asset's covariance with the investor's portfolio measures the asset's total risk and its own return variance measures its potential contribution to the risk in that portfolio.
C) An asset's own return variance represents the systematic component of risk that cannot be diversified away.
D) Investor's should not care about an asset's covariance because it represents the component of risk that cannot be diversified away.