A train is running at 90km h−1. The driver first reduces the speed by applying a retardation of 1m s−2 for the next 200m and then increases the braking so that a retardation of 2m s−2 acts until the train stops. The total distance travelled after the brakes were first applied is closest to
(a) 300m
(b) 256m
(c) 200m
(d) 312.5m