What legal document creates a voluntary lien on real property upon recording?

The mortgage is the correct choice because it is the legal document that establishes a voluntary lien on real property when it is recorded with the appropriate government authority, such as the county clerk or recorder’s office. This recording process is crucial as it provides public notice of the lender's interest in the property, thereby giving it a legal claim against the property should the borrower default on the loan.

A deed, while an important document in real estate transactions, is primarily used to transfer ownership of property rather than to create a lien. The promissory note serves as a promise from the borrower to repay the loan but does not create a lien itself. A contract may outline the terms of the agreement between the borrower and lender but does not, on its own, confer a lien against the property. Thus, when a mortgage is recorded, it effectively ties the loan to the property, ensuring that the lender has a legal right to seek repayment through the property if necessary.