Given : ‘a’ is a positive integer. I. Given : It is an odd number. ‘a’ may or may not be a prime number. e.g. While 3 is a prime, 9 is a non-prime. ∴ I alone is not sufficient. II. Given: It is an even integer greater than 2. ⇒ a = 4, 6, 8, 10,..... ⇒ ‘a’ is not a prime number. ∴ II alone is sufficient