Simon has an extensive collection of rare stamps. When Simon faces financial difficulties, he decides to sell a few of his beloved stamps. Sophie offers to buy a stamp and Simon accepts Sophies offer, but after Sophie pays Simon the agreed amount, Simon refuses to deliver the stamp and tries to return Sophies money to her. Sophie refuses to accept her money and instead tells Simon she wants the stamp. Which of the following statements is true?

a. Simon does not have to give Sophie the stamp because he offered to return the money Sophie paid.

b. Simon does not have to give Sophie the stamp because he changed his mind.

c. Simon has to give Sophie the stamp if Sophie sues him and requests specific performance.

d. Simon has to give Sophie the stamp and her money to reimburse her for the emotional distress caused by Simon refusing to give her the stamp.