Given a text T, and several options, according to the question posed in the text T to choose the most appropriate option from the options as the answer, please directly output the most appropriate option, do not need to output the explanation.

With respect to an equally-weighted portfolio made up of a large number of assets, which of the following contributes the most to the volatility of the portfolio?
Option A:Average variance of the individual assets.
Option B:Standard deviation of the individual assets.
Option C:Average covariance between all pairs of assets.

Answer: C