If the current solution is not optimal in Phase II of the solution of the transportation problem, you need to find a loop (or stepping-stone path) and a new solution or allocation that is cheaper than the current shipping plan. When you select an empty cell with negative cost reduction index (i.e. reduce cost), you can find only one loop (stepping-stone path) stating and ending at the selected empty cell that can lead to a new cheaper solution or shipping plan. True or false