A scooter starting from rest moves wilth as constant acceleration for a time `/_ _1`, then with a constant velocity for the next `/_ _2` and finally with a constant deceleration for the next `/_ _3` to come to rest with resect to the scooter wilthout touching any other part. The force exerted by the seat on the man is
A. 500 N throughout the journey
B. less than 500 N throughout the journey
C. more than 500 N throughtout the journey
D. `gt500 N for time /_\_1 and /_\_3 and 500 N for /_ _2`.
