A Called Up B That He Was Selling His House

A called up B that he was selling his house and lot for ₱10M. Within one (1) hour after B accepted the offer, he invited A for dinner at the Manila Hotel where B paid the dinner in the amount of ₱5,000.00. They agreed that the ₱5,000.00 was the downpayment. A receipt for the payment of ₱5,000.00 for the dinner was issued. When A refused to sell, B sued for specific performance. Is B correct?

A) B is correct because the contract has been partially executed due to the agreement that the ₱5,000.00 paid for their dinner constituted the downpayment.
B) B is not correct since the contract is unenforceable as it was not put to writing.
C) A is wrong because the contract is unenforceable as there was no payment of the price.
D) The contract is valid because it has all the elements of a valid contract.