An ownership interest that is based on annual occupancy intervals is the:

A time-share represents an ownership interest where multiple individuals share the right to use a property for specific time intervals each year. This arrangement allows owners to claim a set period of time for personal use of a vacation property, thus facilitating shared ownership and reducing individual maintenance costs. The structure of a time-share typically means that each owner has the right to occupy the property for a certain number of days or weeks annually, creating a system that diversifies the use of the property and maximizes its availability throughout the year.

In contrast, a leasehold refers to a temporary right to use and occupy land or property, typically under a rental agreement rather than ownership. Condominiums are individually owned units within a larger building or complex but do not have the time-sharing aspect focused on yearly usage. Cooperatives involve ownership of shares in a corporation that owns the property, granting rights to occupy specific units but lacking the distinct annual intervals characteristic of time-shares. Thus, the unique aspect of annual occupancy intervals clearly defines the time-share concept as the correct answer.