Contracts -Roy Offered to Sell Robert His 2001 Toyota Camry for for $1,000

Contracts
-Roy offered to sell Robert his 2001 Toyota Camry for $1,000. Robert told Roy that he would let him know in a few days. After a few days, Robert still had not told Roy whether or not he would buy the car. A month later, Rick found out that Roy was selling his car and asked Roy if he could buy it. Roy agreed and sold the car to Rick for $1,000. The next day Robert told Roy he was wanted to buy the car. Roy told him that he had sold the car to Rick. Robert reminded Roy that they had a contract. Did Roy and Robert have an enforceable contract?

A) No. Roy made an offer to Robert, but the offer lapsed because Robert did not accept it within a reasonable amount of time.
B) Yes. Roy and Robert had a contract. By not performing, Roy is in breach of contract.
C) No. The contract was not in writing.
D) Yes. Because Robert never said that he would not buy the car, it was clear that he accepted Roy's offer.
E) No. Robert's silence meant that he did not accept.