If the pair of straight lines x^{2} - 2pxy - y^{2} = 0 and x^{2} - 2qxy - y^{2} = 0 be such that each pair bisects the angle between the other pair, then

- pq = -1
- p = -q
- pq = 1
- p = q

**Answer**

Equation of bisector of both pair of straight lines,

px^{2} + 2xy - py^{2} = 0

qx^{2} + 2xy - qy^{2} = 0

q/1 = 2/-2p = -q/-1

**The correct option is A.**