2000 Pascal Problem 18

In the diagram the five smaller rectangles are identical in size and shape. The ratio of AB:BC is

\textbf{(A)}\ 3:2\quad \textbf{(B)}\ 2:1\quad \textbf{(C)}\ 5:2\quad \textbf{(D)}\ 5:3\quad \textbf{(E)}\ 4:3

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.