The longest bone in human body is -

Options

A. Radius
B. Ulna
C. Femur
D. Tibia

Explanation

**Step-by-Step Solution:**

1. **Understand the Question**: The question asks for the longest bone in the human body.

2. **Know the Bones**: The human body consists of 206 bones that make up the skeleton. Familiarize yourself with some of the major bones and their locations.

3. **Analyze the Options**: The options provided are:
- Radius
- Ulna
- Femur
- Tibia

4. **Identify the Bones**:
- **Radius**: Located in the forearm.
- **Ulna**: Also located in the forearm, alongside the radius.
- **Femur**: Located in the thigh.
- **Tibia**: Located in the lower leg.

5. **Compare the Lengths**: Among the listed bones, the femur is known to be the longest bone in the human body.

6. **Conclusion**: Therefore, the answer to the question is that the longest bone in the human body is the **femur**.

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