A realized capital gain is:

an increase in the net worth of a sole proprietorship or partnership.

the difference between the selling price and the purchase price of a share of stock.

the difference between the original value of a piece of equipment and its depreciated value.

an increase in the market value of a share of stock held by an individual.

the difference between the price of a share of stock and the amount the investor paid for it$,$ including the broker's fee.