What type of bond is collateralized by a trust holding real estate?

A mortgage bond is indeed the correct answer because it is specifically secured by a lien on real estate assets that serve as collateral for the bondholders. In the event of default, bondholders have a claim to the real estate held in trust, providing them with an added layer of security. This type of bond is often used by companies to raise funds for purchasing or developing property while offering a lower risk to investors due to the tangible asset backing the debt.

In contrast, other types of bonds listed in the options do not have the same specific connection to real estate. Headquarters debentures are typically unsecured bonds that do not have collateral backing. Guaranteed bonds rely on a third party to back the payment of interest and principal but are not intrinsically tied to real estate. Collateral trust bonds are secured by financial assets or securities placed in trust rather than by real estate, making them distinct from mortgage bonds.