Ball-Mart, a baseball card store, had a 1968 Nolan Ryan rookie card in almost perfect condition for sale. Any baseball collector would have known that the card was worth at least $1,000; the published monthly price guide listed its market value at $1,200. Bryan was a twelve-year-old boy with a collection of over 40,000 baseball cards. When Bryan went to Ball-Mart, Kathleen, who knew nothing about cards, was filling in for the owner. The Ryan card was marked "1200," so Bryan asked Kathleen if this meant twelve dollars. She said yes and sold it to him for that amount. When Ball-Mart's owner realized the mix-up, he sued to rescind the contract. Who wins?