Bailey Is Selling His Baseball Cards

Bailey is selling his baseball cards. He writes his friend Molly a letter and tells her she can buy the cards for $100. He closes his later saying: "If you want to buy the cards, let me know by next month. You can give me a call or whatever." Two days later, Bailey receives a letter from Molly saying she will buy the cards for $100. Does Bailey have to sell Molly the cards?

A) No, because there was no definite offer.
B) No, because there was no definite acceptance.
C) No, because Molly did not call Bailey via phone to accept his offer.
D) Yes, but only if Molly goes to pick up the cards and takes him the $100 within two days of the time her letter is received.
E) Yes, because Molly's letter accepting Bailey's offer was received, and Bailey only suggested that Mary call to accept; he did not require it.