In which type of contract is only one party bound by the promises made?

In a unilateral contract, only one party is bound by the promises made, creating an obligation only for that party. This type of contract typically arises when one party makes a promise in exchange for the act of another. For example, if someone offers a reward for the return of a lost pet, the person offering the reward is obligated to pay if someone finds and returns the pet, but the person who finds the pet is not obliged to undertake any specific action; they can choose whether or not to return the pet.

Bilateral contracts, on the other hand, involve mutual obligations where both parties promise to fulfill certain responsibilities, which is not the case in a unilateral contract. Implied contracts are not explicitly stated but are understood through actions or circumstances, while express contracts are clearly laid out either verbally or in writing. Neither of these types focuses on a single obligated party as your answer does. Thus, understanding the characteristics of a unilateral contract clarifies why this answer is the correct one.