Mohammed Wants to Buy His Friend Khurram's Old Computer,but He

Mohammed wants to buy his friend Khurram's old computer,but he currently has no money.He offers to pay Khurram $300 in a month at which time Khurram will give Mohammed his computer.Khurram nods and says,"sure." Two weeks later,Mohammed is paid and buys a new computer.He then refuses to buy Khurram's computer.Which of the following statements is true?

A) Mohammed has breached the contract by refusing to buy Khurram's computer.
B) Mohammed has breached the contract by buying a new computer.
C) There was never a contract;Mohammed has simply revoked the offer.
D) Khurram's action did not constitute acceptance;he was too vague.
E) There was no breach because the computer was unsolicited.