Answer: Point R (choice 4)
Step-by-step explanation:
Points A, C, U, D, S and E are all in the bottom floor plane. A plane is a flat surface, and saying "points are coplanar" means the points are all on the same plane.
Points like R, T and B are not on the floor plane, so they are not coplanar with the other points mentioned in the previous paragraph.
In other words, point R is not coplanar with points C, D and E since R is not on the floor plane with C,D,E.