What is the legally binding contract called that Sara is using to rent an apartment?

The legally binding contract that Sara is using to rent an apartment is known as a lease. A lease is a formal agreement between a landlord and a tenant, outlining the terms and conditions under which the tenant can occupy the property. This document typically details the duration of the rental period, payment terms, responsibilities for maintenance, and other crucial elements that govern the landlord-tenant relationship.

In contrast, a rental contract is a more general term but is often synonymous with a lease; however, it may not encompass all the legal formalities and specific terms that a lease would. A purchase contract pertains to buying property, not renting, and therefore does not apply in this scenario. A rental application is a form that potential tenants submit to a landlord to express interest in renting a property, which allows the landlord to assess their suitability but is not a contract itself.

Hence, the lease serves the specific purpose of establishing a legally binding agreement regarding the rental of the apartment, making it the most accurate choice in this instance.