The inventor of a laser-beam vegetable chopper ran a television ad that described the chopper and said, "This chopper is yours for only $49.99 if you send your check or money order" to a specified post office box. The owner of a retail specialty shop wrote to the inventor, "What's your best, firm price for two dozen choppers?" The inventor sent a written reply that said in its entirety, "We quote you for prompt acceptance $39.99 per unit." Two months later, the shop owner subsequently mailed a check to the inventor in the appropriate amount, with a memo enclosed saying, "I accept your offer for 24 choppers."

a. Is there an enforceable contract?