Cathode rays were discovered by

Options

A. Maxwell Clerk James
B. Heinrich Hertz
C. William Crookes
D. J.J. Thomson

Answer

**Step-by-Step Solution:**

1. **Identify the Question**: The question asks who discovered cathode rays.

2. **Review the Options**: The options provided are likely names of scientists. We need to evaluate each option to find out who is associated with the discovery of cathode rays.

3. **Evaluate Each Scientist**:
- **A. James Clerk Maxwell**: Known for his work in electromagnetism and color photography, but not for cathode rays.
- **B. Heinrich Hertz**: Famous for his studies on radio waves, not related to cathode rays.
- **C. J.J. Thomson**: He discovered the electron, which is related to cathode rays but did not discover them.
- **D. William Crookes**: He is known for his experiments with cathode rays and is credited with their discovery.

4. **Conclusion**: Based on the evaluation, the scientist who discovered cathode rays is William Crookes.

5. **Final Answer**: The correct answer is D. William Crookes.

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