Answer: The correct option is 'his speed was 2 m/s, and his velocity was 0.'
Step-by-step explanation:
In a Round trip the stating point and finishing point are the same.
The distance covered by Kai in 200 seconds = AB+BA =
200 m+200 m = 400 m
Speed of the kai =

Displacement = shortest path covered = AB - BA = 200 m - 200 m =0 m
Velocity of the kai =

Hence, the correct option is 'his speed was 2 m/s, and his velocity was 0.'