Suppose you have a very accurate, reliable estimate for a security's long-term expected return, this estimate has very little variance, and the expected return is commensurate with the security's risk. Explain why it makes sense to buy more of this security if it fails to earn this expected return in the next period.

A) It indicates a buying opportunity due to undervaluation
B) Diversification benefits may still outweigh underperformance
C) Market trends may favor the security in the future
D) Overreaction to short-term fluctuations presents a chance for profit