A man of seemingly modest means died, leaving his nephew as his sole heir. Among the items inherited by the nephew were some old oil paintings. The nephew knew nothing about art and had no place to put the paintings in his home. He placed an ad in the paper offering to sell the paintings at a price to be mutually agreed upon. A buyer for an art gallery responded to the ad. The buyer did not identify himself as an art gallery buyer or tell the nephew that he was knowledgeable about art. Rather, he concocted a story about wanting the paintings for his country estate. The nephew, for his part, revealed his lack of knowledge about art when he told the buyer that his uncle had probably painted the pieces himself. From the signature and the style, the buyer recognized that the artist was a renowned 19th century American portrait artist. The nephew and the buyer agreed upon a price and executed a contract. However, before the nephew delivered the paintings to the buyer, or the buyer paid him, he sought to rescind the contract. The buyer insisted that the nephew deliver the paintings to him and threatened to sue for breach of contract if he did not. Which argument would give the nephew the best basis for rescinding the contract with the buyer