Let $$P$$ be the point $$(1, 0)$$ and $$Q$$ a point on the locus $$y^2 = 8x$$. The locus of mid point of $$PQ$$ is

A

$$y^2 - 4x + 2 = 0$$

B

$$y^2 + 4x + 2 = 0$$

C

$$x^2 + 4y + 2 = 0$$

D

$$x^2 - 4y + 2 = 0$$