Task: Question Answering
Input (English): In one day, a family in a car rode for 2 hours, stopped for 3 hours, and then rode for another 5 hours. During the day, the family traveled a total distance of 400 kilometers. What was their average speed for the whole trip?  
 (A) 10 km/h (B) 20 km/h (C) 40 km/h (D) 50 km/h
Output (English): C