In a group of 800 people, 1/5 play at least one instrument, 64 play two or more. What is the probability that one student play exactly one instrument?	Choose the most appropriate option.
A) 3 / 25
B) 3 / 125
C) 2 / 25
D) 3 / 25
E) 1 / 5

Rationale: "p ( playing 2 or more instruments ) = 64 / 800 = 2 / 25 . then , the probability of playing exactly one instrument is given by : p ( playing 1 or more instruments ) - p ( playing 2 or more instruments ) = 1 / 5 - 2 / 25 = 3 / 25 . answer a ."
Answer: A