If a $$\cot \theta + b \cosec \theta = p$$ and $$b \cot \theta + a \cosec \theta = q$$ then $$p^{2} - q^{2}$$ is equal to __________.

A

$$b^{2} - a^{2}$$

B

$$a^{2} - b^{2}$$

C

$$b - a$$

D

$$a^{2} + b^{2}$$