Let $O$ be the vertex of the parabola $y^2 = 16x$. The locus of centroid of $\triangle OPA$ when $P$ lies on parabola and $A$ lies on $x$-axis and $\angle OPA = 90°$ is
(A) $y^2 = 8(3x - 16)$
(B) $9y^2 = 8(3x - 16)$
(C) $y^2 = 8(3x + 16)$
(D) $9y^2 = 8(3x + 16)$