Which of the following diseases is caused by virus?

Options

A. Diphtheria
B. Polio
C. Tuberculosis
D. Typhoid

Answer

To determine which of the listed diseases is caused by a virus, we will analyze each option provided in the question.

**Step 1: Analyze Diphtheria**
- Diphtheria is an infection caused by bacteria, specifically the bacterium *Corynebacterium diphtheriae*.
- Therefore, diphtheria is not caused by a virus.

**Step 2: Analyze Polio**
- Polio, also known as poliomyelitis, is caused by the poliovirus.
- Since polio is caused by a virus, this option is a potential answer.

**Step 3: Analyze Tuberculosis**
- Tuberculosis (TB) is caused by the bacterium *Mycobacterium tuberculosis*.
- Thus, tuberculosis is not caused by a virus.

**Step 4: Analyze Typhoid**
- Typhoid fever is caused by the bacterium *Salmonella typhi*.
- Therefore, typhoid is also not caused by a virus.

**Conclusion:**
- After analyzing all the options, the only disease caused by a virus is polio.

**Final Answer: Polio (Option 2) is caused by a virus.**

---