2016 Gauss 8 Problem 3

The graph shows the number of hours Stan worked on a school project. For how many hours in total did he work on the project?

\textbf{(A)}\ 6\quad \textbf{(B)}\ 2\quad \textbf{(C)}\ 8\quad \textbf{(D)}\ 9\quad \textbf{(E)}\ 10

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 Gauss contests here.