If a straight line drawn through the point of intersection of the lines $$4x + 3y - 1 = 0$$ and $$3x + 4y - 1 = 0$$, meets the co-ordinate axes at the points P and Q, then the locus of the mid point of PQ is :

A

$$x + y - 7 = 0$$

B

$$x + y - 14xy = 0$$

C

$$2x + y + 14xy = 0$$

D

$$x + 2y - 14xy = 0$$