1988 AHSME Problem 23

The six edges of a tetrahedron ABCD measure 7, 13, 18, 27, 36 and 41 units. If the length of edge AB is 41, then the length of edge CD is

\textbf{(A)}\ 7\qquad \textbf{(B)}\ 13\qquad \textbf{(C)}\ 18\qquad \textbf{(D)}\ 27\qquad \textbf{(E)}\ 36

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