Francisco is a concert violinist who is scheduled to perform at the Kennedy Center for the first time. He buys what he is told is a Stradivarius violin from a well-known, reputable dealer in quality violins, and he pays the going rate for a Stradivarius. He later learns the violin is an imitation, sold by the dealer who was trying to make quick money. In this case: a. Francisco has made a unilateral mistake and cannot avoid the contract. b. the sale is voidable by the seller for mutual mistake. c. the sale may be rescinded, because the dealer has made a nonfraudulent misrepresentation.