A composite number is a natural number, i.e. counting numbers that have more than two factors.
That means a composite number is a number that is divisible by more than two numbers.
In other words, a natural number which is not a prime is a composite number other than 1.
For example: - let us consider the natural number 10. 10 is divisible by 1, 2, 5, and 10 itself which means it has more than two factors.
So, 10 is a composite number.
Some other composite numbers are - 4, 6, 8, 9, 10, 12,….. etc.
4 is the first and smallest composite number.
Hence, option (b) is the correct answer i.e. 4