2003 Cayley Problem 15

In the diagram, line L_1 is parallel to line L_2 and BA = BC. The value of x is

\textbf{(A)}\ 35\quad \textbf{(B)}\ 30\quad \textbf{(C)}\ 37.5\quad \textbf{(D)}\ 45\quad \textbf{(E)}\ 40

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.