A property owner has a mortgage on a lot and wants to borrow money to build a house on it. To accomplish this, which of the following clauses must the existing mortgage contain?

An alienation clause, also known as a due-on-sale clause, allows the lender to demand full repayment of the loan if the property is sold or transferred. This clause does not facilitate additional borrowing; instead, it restricts the transfer of the property, making it irrelevant to the owner's goal of obtaining a construction loan.

An acceleration clause permits the lender to require immediate repayment of the entire loan if certain conditions are met, such as default on payments. While this clause is important for lender protection, it does not address the need to secure additional financing for construction and therefore does not assist in the property owner's intention.

A subrogation clause allows a lender to assume the rights of another lender upon paying off a debt. This clause is primarily relevant in refinancing situations or when consolidating debts but does not pertain to the property owner's ability to secure a new loan for construction purposes.