How to know whether 97 is a prime or not ?
Take sqrt of 97 = 10 (approx)
now check whether 97 is divisible by all prime numbers which are <= 10
If no then it is a prime number ... 97 is not divisible by 2,3,5,7 .. so 97 is a prime number...
So 97 cannot be written as a product of 2 numbers(apart from 97*1)...And so 97 cannot be represented as nm , (apart from 971 ) ...
So only way we could have got 97 functions is using 971 which is possible only if 1 element is in domain and 97 elements in co-domain.
B) says number of fuinctions is 1.
C) says number of functions is 9797.