JEE Math Practice Question

Let A = $$\left\{ {\theta \in \left( { - {\pi \over 2},\pi } \right):{{3 + 2i\sin \theta } \over {1 - 2i\sin \theta }}is\,purely\,imaginary} \right\}$$ . Then the sum of the elements in A is :

1. A.$${5\pi \over 6}$$
2. B.$$\pi $$
3. C.$${3\pi \over 4}$$
4. D.$${{2\pi } \over 3}$$