Which of the following statements is true?
1) I. Ben, obviously angry about his $20,000 car, says that he will sell the car for $500. Ben's statement is an offer.
2) II. Tom's ad to sell his guitar for $50 is an offer.
3) III. Mary says to Jane, "You're my favorite niece; therefore, I offer you $5,000." Mary's statement is not an offer.