On September $1,$ Daxum, Inc., a software developer and dealer, offers to sell a gaming software package to Segar, Inc. for $$50,000.$ The terms of the written offer state that Segar has until October $1$ to accept the offer. On September $15,$ Segar receives a letter from Daxum recalling the offer. On September $20,$ Segar writes back to accept Daxum's September $1$ offer.

Which of the following is true?

Because Daxum's offer letter constitutes a firm offer, it cannot be revoked prior to October $1,$ and Daxum's attempt to revoke the offer is unenforceable.

Because Daxum's offer letter constitutes an option contract, it can be revoked because it is not supported by adequate consideration.

Because this contract is govern by the UCC, the firm offer is unenforceable unless it is supported by adequate consideration.

Because this contract is governed by the CISG, unless Daxum's offer is revoked in the same manner the offer was made, then it is enforceable.