Of the two kinds of fee simple estate, which is a perpetual estate with no usage restrictions?

A fee simple absolute is a type of ownership interest in real property that is the most complete and unrestricted form of ownership. It grants the owner full rights to use, sell, or transfer the property as they see fit, without any conditions or limitations. This means that the owner can enjoy the property indefinitely, and it can be passed down to heirs without any attached requirements.

In contrast, a fee simple conditional includes certain conditions that, if violated, could result in the ownership reverting to a previous owner or grantor. Life estates grant ownership for the duration of an individual's life, after which the property returns to the original owner or their heirs. Leasehold estates are temporary interests granted under a lease agreement, with rights limited by the terms of that lease.

Thus, the key characteristic of a fee simple absolute is its permanence and the absence of usage restrictions, making it the correct answer in this context.