When must both parties to a contract perform certain duties for the contract to be enforceable?

The correct choice is a conditional contract, which stipulates that certain conditions must be met before both parties are obligated to perform their duties outlined in the contract. In this type of agreement, the obligations of the parties are dependent on the occurrence of a specific event or situation. Until that condition is satisfied, neither party is bound to fulfill their contractual duties. This characteristic is crucial as it emphasizes that enforcement of the contract hinges on the completion of a predefined condition.

In contrast, a unilateral contract involves one party making a promise in exchange for an act performed by the other party, creating an obligation only for the party making the promise. A bilateral contract entails mutual obligations, where both parties commit to performing certain duties from the outset. A void contract is one that is not enforceable from its inception, meaning that no party has legal obligations under such an agreement. Thus, the nature of a conditional contract specifically highlights the requirement for certain actions or events to occur for both parties to engage in their contractual duties.