A bus is moving with a velocity `10 ms^-1` on a straight road. A scooterist wishes to overtake the bus in `100 s`. If the bus is at a distance of `1 km` from the scooterist, with what velocity should the scooterist chase the bus ?
A. `50ms^(-1)`
B. `40ms^(-1)`
C. `30ms^(-1)`
D. `20ms^(-1)`
