Answer:C

Feedback:A gives B a start of 25 meters and still wins the race by 10 seconds.

Alternatively, if A gives B a start of 45 meters, then the race ends in a dead heat.

Therefore, the additional 20 meters start given to B compensates for the 10 seconds.i.e., B runs 20 meters in 10 seconds.

Hence, B will take 100 seconds to run 200 meters.

We know that A gives B a start of 45 meters. B will take 22.5 seconds to run this 45 meters as B runs 20 meters in 10 seconds or at the speed of 2 m/s.

Hence, A will take 22.5 seconds lesser than B or 100 - 22.5 = 77.5 seconds to complete the race.