What combination of x and y will yield the optimum for this problem? Maximize $10x + $4y, subject to (1) 5x + 3y s 15 and (2) 3x + 6y s 18 and (3) x, y 20. O x = 3, y =0 O x = 0, y = 3 O x = 0, y =0 O x = 3, y = 3 O x = 5, y = 3