Which covenant promises that the grantor will defend against third-party claims of title?

The correct answer is warrantability. This covenant specifically assures the grantee that the grantor will defend the title against any third-party claims. When included in a deed, this promise means the grantor is responsible for protecting the grantee’s ownership status. If a third party asserts a superior claim to the property, the grantor is obligated to defend the title and may be liable for any losses the grantee incurs as a result of a breach of this covenant.

In contrast, the other options refer to different covenants with distinct implications. The covenant of seisin guarantees that the grantor actually holds the title to the property, while the right to convey implies the grantor has the legal authority to transfer the property. The covenant of quiet enjoyment ensures that the grantee will not be disturbed in their use and possession of the property due to title defects, but it does not specifically address third-party claims, unlike warrantability. Thus, the focus of warrantability on defending against third-party claims makes it the correct choice in this context.