The function f is defined for all the positive integers d by the following rule: f(d) is the number of positive integers each of which is less than d and has no positive factor in common with d other than 1 . if p is a prime number then f(p)? Pick:
A) p-1  B) p-2  C) (p+1)/2  D) (p-1)/2  E) 2
The moment you put a prime number in the function f(d), notice that all the numbers lesser than d have no divisor clashing with divisor of d since d is prime!!.   For instance f(7)= {6, 5, 4, 3, 2, 1}   Thus for f(p) number of integers falling under this set will be p-1   p-1nswer :- p-1
<result>A</result>
The function f is defined for all the positive integers d by the following rule: f(d) is the number of positive integers each of which is less than d and has no positive factor in common with d other than 1 . if p is a prime number then f(p)?