Let $$x = 9$$ be a directrix of an ellipse E, whose centre is at the origin and eccentricity is $$\dfrac{1}{3}$$. Let $$P(\alpha, 0)$$, $$\alpha > 0$$, be a focus of E and AB be a chord passing through P. Then the locus of the mid point of AB is :

A

$$9y^2 = 8x(1 - x)$$

B

$$3y^2 = 4x(1 - x)$$

C

$$9y^2 = 8x(x - 1)$$

D

$$3y^2 = 4x(x - 1)$$