Which rule denotes that an acceptance must be exactly as stated in the offer?

The Mirror Image Rule indicates that an acceptance of an offer must match the terms of the offer exactly, without any modifications or deviations. This principle is fundamental in contract law as it ensures that both parties are in agreement on the terms before a legally binding contract is formed. If the acceptance alters any terms of the original offer, it is not considered valid acceptance; instead, it constitutes a counteroffer. This rule helps to avoid misunderstandings and disputes by establishing that the acceptance must be a clear and unequivocal agreement to the offer as presented.

The other options relate to different aspects of contract formation or negotiation but do not capture the necessity for the terms of acceptance to mirror those of the offer. The Counteroffer Rule deals with situations where the offeree proposes changes, while the Acceptance Standard Rule and Offer and Acceptance Rule are broader concepts regarding the process of forming contracts, not specifically addressing the necessity for an exact match in terms.