X and Y Live in the Same Suburb

X and Y live in the same suburb.X offers to sell Y his luxury yacht and tells Y to respond by post.Y posts a letter accepting the offer.The following evening Y changes her mind and calls X and leaves a message on X's voicemail saying that the offer is not accepted.Which of the following is correct?

A) A contract was formed when Y sent the letter and prior to Y's phone call as that was when Y's acceptance will be deemed to have been communicated according to the postal rule.
B) There is no contract because Y effectively communicated her rejection of the offer.
C) There is no contract because offers cannot be accepted by post.
D) A contract was formed as soon as X received Y's voicemail message.