Which One of the Following Is an Example of Mental

Which one of the following is an example of mental accounting?

A) associating a security's gains or losses based on its purchase price
B) calculating the gain or loss on a security on a daily basis
C) computing the amount of tax due on the gain from a stock sale
D) considering the gain realized when a stock pays a dividend
E) comparing the gains and losses on a portfolio to those of the overall market