Those seem like such natural candidates that it would be surprising if it weren't them. I know it's just a homework exercise to draw the diagrams and check the claims. Maybe tomorrow when I'm feeling more fresh. I had a professor in college who would scribble all kinds of long detailed computations on the board. One day he said: when in doubt, do the dog work.
Since I'm feeling tired and lazy tonight, anyone feel free to cut in and prove or disprove my hypotheses.