Which of the following `"is"//"are"` not radioactive element(s)?

Options

A. Sulphur
B. Tellurium
C. Selenium
D. Polonium

Explanation

To determine which of the elements listed (sulphur, selenium, tellurium, and polonium) are not radioactive, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Radioactivity**: Radioactivity is the process by which unstable atomic nuclei lose energy by emitting radiation. This can include alpha particles, beta particles, or gamma rays.

2. **Identify the Elements**: The elements in question are:
- Sulphur (S)
- Selenium (Se)
- Tellurium (Te)
- Polonium (Po)

3. **Research Each Element**:
- **Sulphur (S)**: This is a stable element and does not exhibit radioactivity.
- **Selenium (Se)**: This is also a stable element and does not exhibit radioactivity.
- **Tellurium (Te)**: This element has stable isotopes and is not considered radioactive.
- **Polonium (Po)**: This is a radioactive element and is known to undergo radioactive decay.

4. **Conclusion**: From the analysis, we find that sulphur, selenium, and tellurium are not radioactive, while polonium is radioactive.

### Final Answer:
The elements that are not radioactive are **sulphur, selenium, and tellurium**.