2008 Pascal Problem 19

An integer is defined to be *upright* if the sum of its first two digits equals its third digit. For example, 145 is an upright integer since 1 + 4 = 5. How many positive 3-digit integers are upright?

\textbf{(A)}\ 28\quad \textbf{(B)}\ 39\quad \textbf{(C)}\ 36\quad \textbf{(D)}\ 45\quad \textbf{(E)}\ 50

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 Pascal contests here.