The angle of declination is

Options

A. `90^(@)` at the poles
B. `0^(@)` at the equator
C. variable
D. None of the above.

Explanation

To solve the question regarding the angle of declination, we will break down the information provided and analyze it step by step.

### Step-by-Step Solution:

1. **Understanding Angle of Declination**:
- The angle of declination is defined as the angle between the geographical meridian (true north) and the magnetic meridian (magnetic north).
- This angle can vary based on geographical location on Earth.

2. **Angle of Declination at the Poles**:
- At the North and South Poles, the magnetic meridian aligns with the geographical meridian.
- Therefore, the angle of declination at the poles is 90 degrees.

3. **Angle of Declination at the Equator**:
- At the equator, the magnetic meridian is horizontal, and it aligns perfectly with the geographical meridian.
- Thus, the angle of declination at the equator is 0 degrees.

4. **Variation of Angle of Declination**:
- As one moves from the equator towards the poles, the angle of declination changes.
- This means that the angle of declination is not constant; it varies depending on the location on Earth.

5. **Conclusion**:
- Given the options provided in the question, the angle of declination is indeed a variable quantity.
- Therefore, the correct answer is that the angle of declination is variable.

### Final Answer:
The angle of declination is a variable quantity.

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