In contract law, what is required for a counteroffer to be valid?

For a counteroffer to be valid, it must consist of a rejection of the original offer and a new proposal. This means that when one party presents a counteroffer, they are not simply accepting the terms of the original offer; rather, they are terminating the original offer and providing different terms or conditions for consideration.

In contract law, acceptance must be unqualified and mirror the terms of the original offer to form a valid contract. A counteroffer changes the terms of the agreement, signaling that the original offer is no longer acceptable to the counteroffering party. Therefore, for a counteroffer to be legally recognized, it must clearly both reject the first offer and introduce new terms.

The other options do not adequately capture the necessary components of a counteroffer. For instance, written confirmation of acceptance, acceptance of all terms from the original offer, and the requirement for an agreement to be signed by both parties are not essential elements for a counteroffer's validity. Instead, they pertain to different aspects of contract formation or acceptance.