Find real thita such that 3+2isin thita / 1-2isin thita is purely real.

Q. Find real $\theta$ such that
$\frac{3+2isin\theta }{1-2isin\theta }$ is purely real.

Q. The value of cos thita cos(90- thita) minus sin thita sin(90- thita) is:
A) 1
B) 0
C) 2
D) -1