Solve the LP problem. If no optimal solution exists, indicate whether the feasible region is empty or the objective function is unbounded. HINT [See Example 1.] (Enter EMPTY if the region is empty. Enter UNBOUNDED if the function is unbounded.) Minimize c = x + y subject to C = x + 4y ≥ 10 4x + y ≥ 10 x ≥ 0, y ≥ 0. (x,y)