Definition of even number – UGC NET Question

An even number is defined as an integer that can be written in the form 2k, where k is an integer. This means it is exactly divisible by 2 without leaving any remainder. Numbers like −4, 0, 2 and 10 are all even because they satisfy this property. Therefore, the description in the question perfectly matches the standard definition of an even number.

Option A:
Prime numbers are integers greater than 1 that have exactly two distinct positive divisors, 1 and the number itself. While some primes like 2 are even, most primes are not characterised simply by divisibility by 2. The defining property in the question is divisibility by 2 for all such numbers, which corresponds to evenness, not primality. Hence, this option is not correct.

Option B:
Odd numbers are integers that leave a remainder of 1 when divided by 2. They can be expressed as 2k+1 for some integer k. This is the opposite of being exactly divisible by 2, so odd numbers do not fit the description given in the question. Therefore, this option must be rejected.

Option C:
Even numbers are correct because they are precisely those integers that divide by 2 with no remainder. In many aptitude questions, recognising even and odd numbers quickly helps in solving problems on divisibility and parity. Knowing this definition is foundational for reasoning about number patterns and algebraic expressions. Thus, this option accurately answers the question.

Option D:
Composite numbers have more than two positive divisors, such as 4, 6 or 12, but the question is not about the count of divisors. Some composite numbers are even and some are odd, so "composite" is not equivalent to "divisible by 2." As the stem focuses solely on divisibility by 2, composite is not the correct term.