Let `O(0,0),P(3,4),` and `Q(6,0)` be the vertices of triangle `O P Q` . The point `R` inside the triangle `O P Q` is such that the triangles `O P R ,P Q R ,O Q R` are of equal area. The coordinates of `R` are `(4/3,3)` (b) `(3,2/3)` `(3,4/3)` (d) `(4/3,2/3)`