The correct answer is option C i.e. RS is the straight line and plane is RSU. Because both the points R and S are on a straight line , so the line is RS. And, there are two conditions for a plane to form: 1) Three non-collinear points, as R, S and U do not lie on the same line so they are non-collinear. And 2) A straight line and a point that does nt lie on the staright line. Here, the straight line is RS and the point is U.