Task: Question Answering
Input (English): A sailboat travels 35 km in 5 hr. Which of the following describes the motion of the sailboat?  
 (A) Its momentum is 7 km/hr. (B) Its acceleration is 7 km/hr. (C) Its displacement is 7 km/hr. (D) Its average speed is 7 km/hr.
Output (English): D