Which of the Following Statements Is the Best Description of a 'Condition

Which of the following statements is the best description of a 'condition'?

A) A term in a contract which cannot be classified until after the breach has occurred and the seriousness of the effects of the breach can be ascertained.
B) An essential term in a contract,non-performance of which may result in rescission and/or damages to the plaintiff.
C) A term which must be satisfied before a contract can come into existence.
D) A term in a contract which provides that the contract will terminate on the happening of a particular event.