Question

How many points can opposite rays have in common? zero, one, two, two or more

Answer 1

This can be explained in better way by drawing two opposite rays having a common point ,or no common point,or more than a single common point, that is point from where these two rays begin.

A ray has one end point and other end goes infinitely in other direction.

As there are two opposite rays starting at a common point, that is there will be No point of Intersection or a single point of Intersection or infinite number of common point between two rays.

So, Only Either Zero or one Point or more than two point that is infinite number of points can be common between two Opposite rays.

Answer 2

Opposite rays are two rays that both start from a common point and go off in exactly opposite directions and the points are collinear 
only one  points can opposite rays have in common as they are opposite in direction
hope it helps