Which of the following documents is unique in that it signals the end of one ownership and the beginning of another?

A mortgage is a financial agreement between a borrower and a lender where the property serves as collateral for a loan. While it can affect ownership rights by placing a lien on the property, it does not transfer ownership itself; rather, it secures the lender's interest until the loan is repaid.

A contract of sale outlines the terms and conditions for the sale of property but does not finalize the actual transfer of ownership. It is a promise to convey ownership but only becomes effective upon execution of the deed, which is the document that formally transfers title.

A completion bond is a financial instrument often used in construction, ensuring that a project will be completed as planned. It does not pertain to ownership transfer; instead, it guarantees that contractual obligations related to construction will be fulfilled, without any impact on property ownership.