Juanita's lawn-mowing service is a profit-maximizing, competitive firm. Juanita mows lawns for $30 each. Her total cost each day is $320, of which $70 is a fixed cost. She mows 10 lawns a day. In the short run, Juanita should A). Shut down or B.) Not shut down. In the long run, Juanita should A.) Exit or B.) Not Exit the industry.