Phyllis Was the Listing Agent on Lou's Home

Phyllis was the listing agent on Lou's home. Phyllis was able to find a young couple to buy Lou's home for his asking price. Just before the closing on the home, Lou changed his mind and refused to sell the property. The young couple had a loan and their down payment was already on deposit with the escrow company. Which of the following is correct regarding Phyllis's commission?

A) Lou does not owe the commission to Phyllis
B) Lou owes only one-half of the commission
C) The down payment will be used to cover the commission
D) Lou owes the commission to Phyllis