Suppose that you wanted to prove the statement, “If a graph…

Suppose that you wanted to prove the statement, “If a graph is planar, then it has chromatic number at most 4.”  Which of the choices below would be the most appropriate start and end of a direct proof of the statement?Start: End: Which of the choices below would be the most appropriate start and end of a proof of the statement by contrapositive? Start: End: Which of the choices below would be the most appropriate start and end of a proof of the statement by contradiction? Start: End: