When tossed, a certain coin has equal probability of landing on either side. If the coin is tossed 3 times, what is the probability that it will land once on heads and twice tails?	Choose one:
A) 1 / 3
B) 1 / 6
C) 1 / 4
D) 1 / 8
E) 1 / 5

Rationale: "must be once on heads and twice on tails 1 / 2 * 1 / 2 * 1 / 2 = 1 / 8 answer : d"
Answer: D