What primarily constitutes consideration in a contract?

Consideration in a contract refers to something of value that is exchanged between the parties involved, which can include benefits, goods, services, or an obligation. The essential element is that there must be a mutual exchange that provides value to both parties. This ensures that both sides are giving up something in order to gain something else, which is fundamental in forming a valid and enforceable contract.

A written agreement, while important for documentation and clarity, is not the essence of consideration. It may help to establish the terms of the exchange or the agreement itself, but it does not constitute the value or benefit being exchanged. Similarly, signing under oath pertains more to the formalization of an agreement rather than to the consideration itself. Lastly, making a verbal promise may be part of an agreement, but without a mutual benefit exchanged, it lacks the necessary substance to be classified as consideration. Therefore, the correct answer reflects the foundational concept of mutual benefit which solidifies the contractual relationship.