If the pair of straight line $x^2-2pxy-y^2=0$ and $x^2-2qxy-y^2=0$ be such that each pair bisects the angle between the other , then the correct relationship is

Question

$\begin{array}{1 1} pq=1 \\ pq=-1 \\ pq=2 \\ pq=-2 \end{array}$