Option: a is the correct answer.
a) all of the points
We know that if a figure or a line lie in a plane then all the points that lie on that figure also lie in the same plane.
i.e. the points are said to be co-planar points.
Ray--
Ray is a line which originates at a point and it goes to infinity from the other end.
Hence, If a ray lays in a plane, then all the points that are on that ray also lie in the same plane.