Perry Armstrong owned the Monona Center, a mall. One of the mall’s eight tenants, Ring’s All-American Karate, occupied about one-third of the space under a fiveyear lease. Ring’s began to experience financial difficulties, and Armstrong agreed to reduce its rent for nine months. Ring’s failed to pay, nonetheless, and when the amount of unpaid rent exceeded $13,000, Ring’s vacated Monona Center. What obligation, if any, did Ring’s have to Armstrong after defaulting on the lease? Why?