Which of the following is true of a unilateral mistake? A. Only one mistake or ambiguity is present in the subject matter of the entire contract. B. Out of several contracts drafted simultaneously between two parties, one has a mistake in its subject matter that does not concern the other contracts. C. Only one party is mistaken about a material fact regarding the subject matter of a contract. D. A single mistake about a material fact in the subject matter of a contract appears several times in the contract.