With Stock Investing,when Does a Capital Gain Occur

With stock investing,when does a capital gain occur?

A) the stock owner is paid dividends without having to sell shares
B) the stock owner sells the stock for a higher price than he paid for it
C) the stock owner sells the stock for a lower price than he paid for it
D) the stock owner receives legal entitlement to physical property of the company
E) a capital gain is not possible with stock investing