GIVEN: If P is a point on x axis such that its distance from the origin is 3 units.
TO FIND: The coordinates of a point Q on OY such that OP= OQ.
On x axis y coordinates is 0. Hence the coordinates of point P will be (3, 0) as it is given that the distance from origin is 3 units.
Now then the coordinates of Q on OY such that OP = OQ
On y axis x coordinates is 0. Hence the coordinates of point Q will be (0, 3)
Hence correct option is (a)