1964 AHSME Problem 18

Let n be the number of pairs of values of b and c such that 3x+by+c=0 and cx-2y+12=0 have the same graph. Then n is:

\textbf{(A)}\ 0\qquad \textbf{(B)}\ 1\qquad \textbf{(C)}\ 2\qquad \textbf{(D)}\ \text{finite but more than 2}\qquad \textbf{(E)}\ \infty

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.