What is the SI base unit for length?

Options

A. inch
B. foot
C. metre
D. kilometer

Answer

**Step-by-Step Solution:**

1. **Understanding the Question**: The question asks for the SI base unit for length. SI stands for the International System of Units, which is a standard used worldwide for measurement.

2. **Identifying the Options**: The options provided are:
- Inch
- Foot
- Meter
- Kilometer

3. **Evaluating Each Option**:
- **Inch**: This is a small unit of length commonly used in the United States.
- **Foot**: This is also a small unit of length, primarily used in the United States and the UK.
- **Meter**: This is the base unit of length in the SI system.
- **Kilometer**: This is a larger unit of length, often used to measure distances.

4. **Determining the Correct Answer**: Among the options, the meter is recognized as the SI base unit for length. While inch, foot, and kilometer are also units of length, they are not the SI base unit.

5. **Final Answer**: Therefore, the SI base unit for length is the **meter**.

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