Four fair dice D1, D2, D3, D4 each having six faces numbered 1, 2, 3, 4, 5 and 6 are rolled simultaneously. The probability that D4 shows a number appearing on one of D1, D2 and D3 is
(a) 91/216
(b) 108/216
(c) 125/216
(d) 127/216