Which of the following has a definite length?
`{:(harr),(AB):}`

Answer

To determine which of the given options has a definite length, we need to analyze the concepts of line, line segment, and ray in geometry.

### Step-by-Step Solution:

1. **Identify the Terms**:
- We have three geometric terms: line, line segment, and ray.

2. **Understanding a Line**:
- A line extends infinitely in both directions. It does not have endpoints, which means it does not have a definite length.

3. **Understanding a Line Segment**:
- A line segment has two specific endpoints and does not extend beyond these points. Therefore, it has a definite length, which is the distance between the two endpoints.

4. **Understanding a Ray**:
- A ray has one fixed endpoint and extends infinitely in one direction. Like a line, it does not have a definite length because it continues indefinitely.

5. **Conclusion**:
- Among the three geometric terms, only the line segment has a definite length. The line and ray do not have definite lengths.

### Final Answer:
The line segment (AB) has a definite length.

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