Which of the following must be present for a contract to be binding?

For a contract to be binding, mutual consideration is an essential element. Mutual consideration refers to the concept that both parties involved in the contract must provide something of value to one another. This exchange can be in the form of money, services, or something else of value. In the context of a life insurance policy, this means the insurer agrees to provide coverage (the promise to pay a death benefit) in exchange for the policyholder's payment of premiums.

Without mutual consideration, there is no contractual agreement since one party cannot simply benefit from the promises of the other without offering something in return. This foundational element underpins the legal enforceability of contracts across various scenarios, ensuring that both sides have obligations that create a balanced and fair agreement.

The other options do not fulfill the necessary condition for contract validity. A health declaration may be required for underwriting purposes but does not constitute consideration itself. Similarly, while having a legal witness signature or notarization can enhance the formality of a contract, these elements are not strictly required for the contract’s validity, nor do they establish the necessary binding principles that mutual consideration provides.