Buyer wants loan contingency to protect earnest money. Should include:

A purchase-money clause refers to a provision that outlines the terms of financing for the buyer, typically relating to seller financing, rather than protecting the buyer's earnest money in case a loan doesn't go through. It does not specifically address the risk of loan denial, thus failing to safeguard the earnest money.

A pre-qualification letter is an initial document from a lender indicating that a buyer is likely to qualify for a loan based on their financial situation. However, this document does not provide any contractual protection regarding the earnest money; it merely indicates potential borrowing capability without guaranteeing financing.

A waiver of lien is a legal document that relinquishes a party's right to place a lien on the property, often used in construction or financing contexts. This option does not relate to protecting earnest money or securing loan approval and therefore is irrelevant in the context of the buyer's need for a loan contingency.