Mr Seller Offered a Parcel of Land to Mr

Mr. Seller offered a parcel of land to Mr. Buyer No. 1 under a contract to sell. Subsequently, Mr. Seller sold the same land to Mr. Buyer No. 2 who paid the price. After a couple of days, Mr. Buyer No. 1 paid the price. Which is correct?

A) The one with a better right is Buyer No. 2
B) Mr. Seller has done a double sale.
C) The one with the better right is the buyer who registers the sale first in good faith.
D) There is no double sale.