Merchant A offers to sell certain goods greater than $500 to Merchant B and further promises that he'll keep the deal open until June 1.Merchant B meant to get around to sending a confirming memo or acceptance but never did.He wakes up in the middle of the night of June 1st-June 2nd in a cold sweat and realizing his mistake.He immediately faxes his acceptance to Merchant A.The fax machine's time stamp reads: 2:32 AM, June 2.Merchant B is left sitting in the dark worrying about his legal situation.

Which rule of contract formation controls the outcome of this situation?

1)Statute of Frauds requires verbal negotiations to be put in writing to be enforceable.

2)UCC does not require extra consideration to keep an offer open.

3)An offer will terminate upon its expiration date.

4)Revocation is effective upon receipt.