Eight players P1, P2,.............P8 play a knock-out tournament. It is known that whenever players Pi and Pj play, the player Pi will win if i < j. Assuming that the players are paired at random in each round, the probability that the player P4 reaches the final is
(a) 1/8
(b) 35/12
(c) 1/3
(d) 4/35
