A traveller covers a total distance of $200\,\text{km}$ on a motorway and completes the first $90\,\text{km}$ at an average speed of $80\,\text{km h}^{-1}$. What average speed is required for the rest of the journey if the traveller is to arrive at the destination in a total time of $2$ hours $60$ minutes?
- A$110\,\text{km h}^{-1}$
- B$120\,\text{km h}^{-1}$
- C$122\,\text{km h}^{-1}$
- D$126\,\text{km h}^{-1}$