Seller and Buyer Negotiate for the Sale of 100 Acres

Seller and Buyer negotiate for the sale of 100 acres of land.They orally agree on a price of $100,000,one half in cash at closing and the other half 90 days after closing.Buyer sends Seller a letter in which all the terms are included and is signed by Buyer.Seller never responds.When the closing date arrives,Seller refuses to transfer title.Buyer sues.This contract is:

A) enforceable,because Buyer had partly performed the contract by sending the letter to Seller
B) unenforceable,because there is no writing signed by Seller
C) enforceable,because Buyer sent a memorandum sufficient against himself,which binds Seller unless Seller objects,which he did not
D) unenforceable,because the parol evidence rule applies