Which one of the following is a prime number?

Options

A. 99
B. 162
C. 173
D. 201

Answer

To determine which of the given options is a prime number, we will analyze each option based on the definition of prime numbers. A prime number is defined as a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers. In other words, a prime number has exactly two distinct positive divisors: 1 and itself.

### Step-by-Step Solution:

1. **Identify the Options**:
Let's assume the options given are: 99, 162, 173, and 201.

2. **Check Each Option**:
- **Option 1: 99**
- Divisors: 1, 3, 9, 11, 33, 99
- Since 99 can be divided by numbers other than 1 and itself, it is not a prime number. It is composite.

- **Option 2: 162**
- Divisors: 1, 2, 3, 6, 9, 18, 27, 54, 81, 162
- Since 162 can also be divided by numbers other than 1 and itself, it is not a prime number. It is composite.

- **Option 3: 173**
- Divisors: 1, 173
- Since 173 can only be divided by 1 and itself, it is a prime number.

- **Option 4: 201**
- Divisors: 1, 3, 67, 201
- Since 201 can be divided by numbers other than 1 and itself, it is not a prime number. It is composite.

3. **Conclusion**:
After analyzing all the options, the only number that is a prime number is **173**.

### Final Answer:
The prime number among the options is **173**.