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A) if N has two distinct +ve factors then N is prime number.
Prime numbers are 2, 3, 5 .... So we dont know if n>=2
B) Difference between any two distinct +ve factors is odd
4 has factors as 1,2 and 4
4-1 = 3 4-2 = 2 so 4 cannot be it.
All even numbers except 2 have more than 2 factors and the difference between any factors may or may not be even
One more Ex N = 6 which as 1,2,3 and 6 as factors. 6-2 = 4 which even
and 6-3 = 3 which odd
Take any prime number. Since prime N is always odd and has only two distinct +ve factors N and 1 N-1 is always even. Except for 2
This rule holds good for only 2.
So B is sufficeint.
110 has 11,10,5 and 2 as factors
11-10 = 1 odd
10-2 = 8 even.