What is a Call option, as it relates to stock and capital gains ?

A Call option is an option to purchase a specified number of shares (usually 100) on or before some future date at a stated price. Call options usually have initial lives of one to nine months. Options are created and sold in certain option markets and can be purchased by investors to obtain the right to buy or sell a specific number of shares of common stock on or before some future date at a stated price.