2003 Pascal Problem 15

In the diagram, square ABCD is made up of 36 squares, each with side length 1. The area of the square KLMN, in square units, is

\textbf{(A)}\ 12\quad \textbf{(B)}\ 16\quad \textbf{(C)}\ 18\quad \textbf{(D)}\ 20\quad \textbf{(E)}\ 25

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.