Two motorists A and B are practicing with two different sports car Mercedes and Maruti, on the circular racing track, for the car racing tournament to be held next month. Both A and B start from the same point on the circular track. A completes 1 round of the track in 1 min and B takes 2 min to complete a round. While A maintains speed for all the rounds, B halves his speed after the completion of each round. How many times A and B will meet between 6th round and 9th round of B (6th and 9th round is excluded)? Assume that the speed of B remains steady throughout each round and changes only after the completion of that round.

a)382
b)347
c)260
d)280