[Pet Products] Sonya, Who Has a Successful Pet Products Business

[Pet Products] Sonya, who has a successful pet products business, is planning to expand her operations from the U.S. into Canada and perhaps Mexico. A friend of hers, Troy, told her that she should carefully investigate the laws in those countries before she proceeded. Sonya responded, however, that she was not concerned because by international treaty, and under NAFTA, so long as she is a U.S. citizen, she only has to obey the U.S. laws. Laws of other countries would not apply to her business operations. Sonya also replied that any other country would have the same contract laws as exists in the U.S. She tells him that the Uniform Commercial Code (UCC) applies to all contracts and that as long as she has a written contract, she is covered. Sonya receives a contract from a Mexican company, signs it, drops it in the mail, and tells Troy the contract is complete.
-Is Sonya correct that her contract with the Mexican company is complete when she drops it in the mail?

A) No, if the CISG applies.
B) No, if the UCC applies.
C) No, because neither the UCC nor the CISG would apply.
D) Yes, because both the UCC and the CISG would apply.
E) Yes, because a contract need not be in writing under the CISG.