Virus was discovered by

Options

A. Stanley
B. Ivanowski
C. Lamarck
D. Beijerinck

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks about who discovered the virus. This requires knowledge of historical figures in microbiology and virology.

2. **Defining a Virus**: A virus is defined as a submicroscopic infectious agent that can only replicate inside the living cells of an organism. Understanding this definition is crucial to grasp the significance of the discovery.

3. **Reviewing the Options**: The options provided are:
- A) Stanley
- B) Iwanowski
- C) (another name)
- D) Vigorinic

4. **Analyzing Each Option**:
- **Option A (Stanley)**: This option is incorrect. While Stanley did important work related to viruses, he is not credited with their discovery.
- **Option B (Iwanowski)**: This option is correct. Iwanowski was a student who conducted research on tobacco mosaic disease, which led to the discovery of viruses.
- **Option C**: This option is incorrect as it does not relate to the discovery of viruses.
- **Option D (Vigorinic)**: This option is also incorrect and does not pertain to the discovery of viruses.

5. **Conclusion**: After reviewing the options, the correct answer is **Option B (Iwanowski)**, as he was the first to discover a virus through his work on tobacco mosaic disease.