Which of the following number is neither prime nor composite?

Options

A. 2
B. 1
C. 3
D. 5

Answer

To determine which of the given numbers is neither prime nor composite, we need to understand the definitions of prime and composite numbers.

1. **Definition of Prime Numbers**: A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. For example, 2, 3, 5, and 7 are prime numbers.

2. **Definition of Composite Numbers**: A composite number is a natural number greater than 1 that has more than two positive divisors. For example, 4, 6, 8, and 9 are composite numbers.

3. **Identifying the Options**:
- **Option A: 2** - This is a prime number because its only divisors are 1 and 2.
- **Option B: 1** - This number is neither prime nor composite. It has only one positive divisor, which is itself (1).
- **Option C: 3** - This is a prime number because its only divisors are 1 and 3.
- **Option D: 5** - This is also a prime number because its only divisors are 1 and 5.

4. **Conclusion**: The only number from the options that is neither prime nor composite is **1**.

Therefore, the answer is **Option B: 1**.