Ty, a merchant, wrote to Marcus: "August 1, I offer to sell you one Model A Desktop Computer system, price $1,000. This is a firm offer for 30 days from the above date. (Signed) Ty." (a) On August 10, Marcus received a letter from Ty: "I hereby revoke my offer of August 1." On August 17, Marcus wrote to Ty: "I hereby accept your offer of August 1." Is there a contract? Explain. Judgment to whom?