Who may become parties to a contract?

In the context of contracts, the ability to form a valid agreement hinges on certain legal principles. Individuals who are parties to a contract must possess the mental capacity to understand the terms of the agreement, which relates to their ability to comprehend what they are agreeing to. Additionally, it is essential that these individuals enter into the agreement voluntarily and without duress or coercion. When someone is under duress, they may not be able to make a fully informed and voluntary decision about their participation in the contract, which invalidates the consent needed for a legal contract.

While other options might include broader definitions or possibilities for entering agreements, option B specifically emphasizes the importance of understanding and voluntary agreement, which are core principles in contract law. Thus, parties must not only be able to understand the contract terms but also be free from pressure that could impair their ability to consent. This makes option B the correct answer in the context of who may validly become parties to a contract.