Let the locus of the mid-point of the chord through the origin O of the parabola $$y^{2}= 4x$$ be the curve S. Let P be any point on S. Then the locus of the point, which internally divides OP in the ratio 3 :1, is:

A

$$3y^{2}=2x$$

B

$$2y^{2}=3x$$

C

$$3x^{2}=2y$$

D

$$2x^{2}=3y$$