Which One of the Following Statements Accurately Describes the Operation

Which one of the following statements accurately describes the operation of a condition subsequent?

A) This occurs when some event that the parties have not anticipated makes performance radically different from what they agree to.
B) This occurs when one party shows up at the right time and place ready, able, and willing to carry out his obligations under the contract.
C) This is a term in a contract that must be met before the contract becomes fully operational.
D) There is no such thing recognized in the common law.
E) This is a term in the contract that provides for the premature cessation (ending) of the parties' obligations upon the occurrence of some particular event.