A bus is moving with a speed of `10 ms^-1` on a straight road. A scooterist wishes to overtake the bus in `10 s`. If the bus is at a distance of `1 km` from the scooterist with what speed should the scooterist chase the bus ?
A. `10ms^(-1)`
B. `20ms^(-1)`
C. `40ms^(-1)`
D. `25ms^(-1)`
