What invalidates contracts due to improper pressure?

The answer is indeed correct because undue influence involves a situation where one party exerts excessive pressure on another, effectively impairing the latter's ability to make free and informed decisions. This pressure usually arises in relationships where one person holds power or authority over another, either due to a position of trust or a personal relationship. As a result, when a contract is formed under undue influence, the agreement can be considered invalid as it lacks the essential element of genuine consent.

The other options touch on different legal principles but do not specifically address the concept of pressure that renders consent invalid. Misrepresentation of facts refers to presenting false information that induces one party to enter a contract, which affects the truth of the contract but does not pertain to the coercive element present in undue influence. Urgent circumstances might create a compelling situation for making quick decisions, but they don't necessarily imply pressure that compromises consent. Disagreement on terms simply reflects a lack of mutual accord rather than invalidity due to coercive influences. Thus, undue influence is the specific legal concept that accurately describes the invalidation of contracts due to improper pressure.