A condition that MUST be met before the sale contract is enforceable is known as a(n):

An amendment refers to a change or addition made to an existing contract. While amendments can modify the terms of a contract, they do not represent conditions that must be satisfied for the contract to be enforceable. Instead, they are adjustments made after a contract is already in place.

A rider is an additional provision added to a contract to address specific issues or clarify terms. Like amendments, riders modify the original agreement but do not serve as prerequisites for enforceability. They supplement the contract rather than establish conditions that must be met beforehand.

A resolution typically refers to a formal decision or determination made by a governing body or organization. In the context of contracts, it does not pertain to conditions for enforceability. Instead, it may relate to the outcome of disputes or decisions made after the contract is already in effect.