Answer:
B
Explanation:
A. His speed is 0 m/s
B. His velocity is 12 m/s
C. His velocity is 0 m/s
D. His acceleration is 12 m/s
Total distance traveled by John = 120 + 120 = 240 meters
Total time taken by John to cover the distance = 10 + 10 = 20 s
Average speed of John = total distance traveled/total time taken
= 240/20 = 12 m/s
Hence, the average speed/velocity of John throughout the journey is 12 m/s.
The correct option is B.