Which of the Following Is the Best Definition of Option

Which of the following is the best definition of option contract?

A) Long-term financial risk arising from permanent changes in prices or other economic fundamentals.
B) A legally binding agreement between two parties calling for the sale of an asset or product in the future at a price agreed upon today.
C) A forward contract with the feature that gains and losses are realized each day rather than only on the settlement date.
D) Reducing a firm's exposure to price or rate fluctuations.
E) An agreement that gives the owner the right, but not the obligation, to buy or sell a specific asset at a specific price for a set period of time.