Which shows solutions to x + 4y = 9 if x and y must be whole numbers.. . . . A.. . . {(0, 9), (1, 4), (2, 1)}. . . B.. . . {(1, 2), (5, 1), (9,0)}. . . C.. . . {(0, 9), (1, 5), (2, 1)}. . . D.. . . {(2, 1), (1, 6), (0, 9)}.