2006 Cayley Problem 12

From 7:45 p.m. to 9:30 p.m., Jim drove a distance of 84 km at a constant speed. What was this speed, in km/h?

\textbf{(A)}\ 60\quad \textbf{(B)}\ 80\quad \textbf{(C)}\ 112\quad \textbf{(D)}\ 63\quad \textbf{(E)}\ 48

If there are no answer choices shown, enter a numerical answer.

Full credit to this problem is given to the CEMC, you may view all Cayley contests here.