# If the coordinates of the points $A, B, C, D$ be (1, 2, 3), (4, 5, 7), (-4, 3, -6) and (2, 9, 2) respectively, then find the angle between the lines $AB$ and $CD$.
$\begin{array}{1 1} (A) \;0^{\large\circ}\; or \;180^{\large\circ} \\ (B) \;90^{\large\circ}\;or \;270^{\large\circ} \\ (C)\; 60^{\large\circ}\; or \;120^{\large\circ} \\ (D)\; 30^{\large\circ}\; or \;150^{\large\circ} \end{array}$