Mall owner: Our mall' s occupancy rate is so low that we are barely making a profit. We cannot raise rents because of an unacceptably high risk of losing established tenants. On the other hand, a mall that is fully occupied costs about as much to run as one in which a rental space here and a rental space there stands empty. Clearly, ttherefore, to increase profits we must sign up new tenants. Which of the following, if true, most seriously weakens the argument? ['The mall is located in a geographic area in which costs incurred for air-conditioning in the hot summers exceed those incurred for heating in the mid winters by a wide margin.', "The mall's occupancy rate, though relatively low, has been relatively stable for several years.", "The mall's operating costs could be cut by consolidating currently rented spaces in such a way that an entire wing of the mall could be closed up.", "None of the mall's established tenants is likely to need additional floor space there in the foreseeable future."]