Which one is a viral disease ?

Options

A. Diptheria
B. Typhoid
C. Cholera
D. Measles

Answer

### Step-by-Step Solution:

1. **Identify the Options**: The question asks to identify which one of the given options is a viral disease. The options provided are:
- Diphtheria
- Typhoid
- Cholera
- Measles

2. **Analyze Each Option**:
- **Diphtheria**: This is a bacterial infection caused by the bacterium *Corynebacterium diphtheriae*. Therefore, it is not a viral disease.
- **Typhoid**: This is also a bacterial infection caused by *Salmonella typhi*. Hence, it is not a viral disease.
- **Cholera**: This is another bacterial infection caused by *Vibrio cholerae*. Thus, it is not a viral disease.
- **Measles**: This is caused by a virus known as *Morbillivirus*. It is a viral disease and primarily affects children, presenting symptoms such as fever, cough, conjunctivitis, and sometimes a rash.

3. **Conclusion**: After analyzing all the options, the only viral disease among them is measles, caused by *Morbillivirus*.

4. **Final Answer**: The correct answer to the question "Which one is a viral disease?" is **Measles**.