Which best describes the strike price on an option contract?

A.) The strike price is the price that must be paid for a common share when it is bought by exercising a right.

B.) The strike price is the price that must be paid for an option contract when it is bought or sold.

C.) The strike price is the price that must be paid for a common share when it is bought by exercising the option

D.) The strike price is the price that must be paid for a common share when it is bought by exercising a conversion warrant.