If $$\sin\theta$$ and $$\cos\theta$$ are roots of the equation $$px^2+qx+r=0$$, then

A

$$p^2-q^2+2pr=0$$

B

$$(p+r)^2=q^2-r^2$$

C

$$p^2+q^2-2pr=0$$

D

$$(p-r)^2=q^2+r^2$$