A certain roller coaster has 4 cars, and a passenger is equally likely to ride in any 1 of the 4 cars each time that passenger rides the roller coaster. If a certain passenger is to ride the roller coaster 4 times, what is the probability that the passenger will ride in each of the 4 cars?  Choose one:
A) 0 B) 1 / 9 C) 2 / 9 D) 3 / 32 E) 1

Rationale: "if he is to ride 4 times and since he can choose any of the 4 cars each time , total number of ways is = 4 * 4 * 4 * 4 = 256 now the number of ways if he is to choose a different car each time is = 4 * 3 * 2 * 1 = 24 so the probability is = 24 / 256 = 6 / 64 = 3 / 32 = 3 / 32 answer : d"
Answer: D