JEE Math Practice Question

$$ABCD$$ is a trapezium such that $$AB$$ and $$CD$$ are parallel and $$BC \bot CD.$$ If $$\angle ADB = \theta ,\,BC = p$$ and $$CD = q,$$ then AB is equal to:

1. A.$${{\left( {{p^2} + {q^2}} \right)\sin \theta } \over {p\cos \theta + q\sin \theta }}$$
2. B.$${{{p^2} + {q^2}\cos \theta } \over {p\cos \theta + q\sin \theta }}$$
3. C.$${{{p^2} + {q^2}} \over {{p^2}\cos \theta + {q^2}\sin \theta }}$$
4. D.$${{\left( {{p^2} + {q^2}} \right)\sin \theta } \over {{{\left( {p\cos \theta + q\sin \theta } \right)}^2}}}$$