If the average of p, q and r is A and pq + qr + rp = 0 then the value of $$\frac{p^{2} + q^{2} + r^{2}}{27}$$ is:

A

$$A^{2}$$

B

$$3A^{2}$$

C

$$9A^{2}$$

D

$$\frac{A^{2}}{3}$$