A, B, C walk 1 km in 5 minutes, 8 minutes and 10 minutes respectively. C starts walking from a point, at a certain time, B starts from the same point 1 minutes later and A starts from the same point 2 minutes later than C. Then A meets B and C at times.

Speed of A = 1000m / 5 = 200m/min
Speed of B = 1000/8 = 125 m/min
Speed of C = 1000/10 = 100 m/min
A starts 2 minutes later than C. Hence, C would have covered 200m during this time. A will catch up this 200 m in 2 minutes after he starts to walk. A will meet C after 2 minutes.
B would have covered 125m by the time A starts to walk. A will cover those 125m in 5/3 minutes after he starts to walk (125 / (200-125)). Hence, option A is the right answer.