Juan thinks he would like to purchase Tara's house, but doesn't know whether he will be able to save enough money for a down payment on a loan. Juan agrees to give Tara $5,000 for the option to purchase her house for $150,000 sometime within the next five years. Juan and Tara reduce their agreement to writing, sign it, and Juan gives Tara $5,000. Two years later, Juan wins the lottery and now is financially able to purchase Tara's house. However, that same day Juan receives a letter from Tara revoking her offer to sell for $50,000. Which of the following is true?
A. Tara's revocation isn't effective.
B. Tara's revocation is effective as long as she refunds the $5,000.
C. Tara's revocation is effective.
D. Juan can't complain because he failed to accept Tara's offer before it was revoked.