Here's a problem to solve: An athlete can run 9 kilometers in 1 hour. If the athlete runs at that same average speed for 30 minutes, how far will the athlete travel?

Among the 4 following options, which is the correct answer?

- A: 18 kilometers
 
- B: 9 kilometers
 
- C: 4.5 kilometers
 
- D: 3.3 kilometers
 