5. (10 points) Freshmen go on a long-distance walking drill to the outskirts after the start of the semester. When they arrive at point $A$, they are 6 minutes late compared to the planned time of 10:10. When they arrive at point $C$, they are 6 minutes early compared to the planned time of 13:10. There is a point $B$ between $A$ and $C$ where they arrive exactly on time according to the plan. What is the time when they arrive at point $B$? ( )
A. 11:35
B. 12:05
C. 11:40
D. 12:20
【Analysis】First, analyze the time difference is 12 minutes, then to arrive exactly on time, it is necessary to make up the first 6 minutes of the time difference.

【Solution】Solution: According to the problem, we know:
Start 6 minutes late, end 6 minutes early, so the time difference is 12 minutes.
The total time from starting point $A$ to $C$ is 3 hours.
Then the on-time time is when the time difference is 6 minutes.
6 minutes compared to 12 minutes is exactly half the time, that is, 1.5 hours after 10:10 is exactly on time.

That is, the time is 11:40.
Therefore, the answer is: $C$.