Viroid' a new infections agent that is smaller than virus and cause-potato spindle tuber disease was discovered by.

Options

A. Pasteur
B. D. J. Lvanowsky
C. T. O. Diener
D. W. M. Stanley

Answer

To solve the question regarding the discovery of 'viroid', which is an infectious agent smaller than a virus and causes potato spindle tuber disease, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Question**: The question asks for the name of the scientist who discovered 'viroid', which is known to cause potato spindle tuber disease.

2. **Identifying the Options**: The options given are:
- A) Pasteur
- B) D.J. Lawan Noski
- C) T.O. Diener
- D) W.M. Stanley

3. **Recalling Relevant Information**:
- Viroids are indeed smaller than viruses and are known to cause specific plant diseases.
- The specific disease mentioned is potato spindle tuber disease.

4. **Connecting the Information**:
- T.O. Diener is credited with the discovery of viroids in 1971. He identified the infectious agent responsible for potato spindle tuber disease.

5. **Selecting the Correct Answer**: Based on the information, the correct answer is C) T.O. Diener.

### Final Answer:
The scientist who discovered 'viroid', which causes potato spindle tuber disease, is **T.O. Diener**.

---