The treatment of cancer with X-rays or `gamma`-rays is called:

Options

A. Radiotherapy
B. Chemotherapy
C. Hormone therapy
D. Immunotherapy

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the term used for the treatment of cancer using X-rays or gamma rays.

2. **Identifying the Options**: The options provided are:
- A) Radiotherapy
- B) Chemotherapy
- C) Hormone therapy
- D) Immunotherapy

3. **Analyzing Each Option**:
- **A) Radiotherapy**: This is a treatment that uses high doses of radiation, such as X-rays or gamma rays, to kill or damage cancer cells.
- **B) Chemotherapy**: This involves using chemical substances to treat diseases, primarily cancer, but is not specifically related to radiation.
- **C) Hormone therapy**: This treatment involves manipulating hormone levels to treat certain types of cancer, not using radiation.
- **D) Immunotherapy**: This is a treatment that uses the body's immune system to fight cancer, which does not involve radiation.

4. **Selecting the Correct Answer**: Based on the definitions and the specific use of X-rays and gamma rays, the correct answer is **A) Radiotherapy**.

5. **Conclusion**: The treatment of cancer with X-rays or gamma rays is called radiotherapy.

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