Is the positive integer 'n' an odd integer
1. n + 4 is a prime number
2. n + 3 is not a prime number




(1) as:
We are given n + 4 is a prime number. We know that all prime numbers greater starting with 5 (as n is a positive integer, it has to start with 1) are odd, and an odd number - 4 is odd, hence sufficient

(2)
since it's data sufficiency, the question of whether n is odd is equivalent to the question of whether n + 3 is odd (they're just opposites: if one is odd, the other is even, and vice versa).
so, just pick two NON-prime numbers for n + 3 - one even, one odd - and that will show insufficiency.
if n + 3 = 10 (not prime), then n = 7. odd.
if n + 3 = 9 (not prime), then n = 6. not odd.
Ans -A