What can terminate a tenancy at will?

A tenancy at will is a rental agreement that can be terminated by either the tenant or the landlord at any time, typically with minimal notice. This flexibility is a defining characteristic of a tenancy at will. The possibility for either party to issue a notification to end the tenancy is crucial; it ensures that both the landlord and the tenant have the autonomy to exit the agreement without having to provide a specific cause.

In many jurisdictions, the requirement for notice is often brief, reflecting the informal nature of this type of tenancy. Therefore, the correct answer highlights the important mechanism of giving notice as a means to terminate the tenancy at will, emphasizing the equal rights of both parties in the agreement.

Other options, while they each reflect circumstances that could indirectly affect a tenancy, do not capture the fundamental characteristic of termination through mutual notification. In practice, a tenant’s resignation or a landlord's decision does not specifically signify the formal termination process required in this scenario, and property sale does not automatically end a tenancy at will unless stipulated by local laws or terms of the lease.