State the decision and reasons

\"Essay Problem 4: S, a manufacturer of kitchen equipment for restaurants, wrote to B: \"September E, I offer to sell you one mixer industrial strength, price $2,000. This is a firm offer for one month until October I. [Signed] S." The letter was received on September 2. On September H], B received a letter from S: \"I hereby revoke my offer of September E.\" On September 17, B wrote to S: \"I hereby accept your offer of September 1." The letter was mailed on September 17 by authorized means. A. Is a contract formed? Explain. B. Instead of the facts stated in (a), assume that S's offer stated that it was a rm offer for four months, and that on December 15, B mailed an acceptance. Is there a contract? Explain. C. Instead of the facts stated in (a) assume that S's offer stated that it was a rm offer for four months, and that on December 14, B received a letter from S, dated December 12 which stated: \"I hereby revoke my offer of September 1." On December 15, B mailed an acceptance. Is there a contract? Explain. (25 points)"