Bud Calls Lou and Says, "I'll Sell You My Car

Bud calls Lou and says, "I'll sell you my car for a thousand bucks, interested?" Lou says, "I'll look it up on the Internet. If the Blue Book price is close, I'll pay you $1,000 in the morning." At sunrise Lou shows up with $1000.

A) Bud must sell him the car because Lou accepted the evening before when he promised to look up the car's value.
B) Bud must sell him the car because he cannot revoke his offer after Lou accepted.
C) Bud does not have to sell the car because his promise was unclear.
D) Bud does not have to sell the car because the payment is based on past consideration.