Mr. Johnson's ninth-grade students are taking an exam. He notices that several students are looking around the room, so he decides to make a comment. Which of the following comments made by Mr. Johnson will most likely maintain a positive relationship between him and his students?
A. "If I catch you cheating, I'll take your paper and give you a zero."
B. "If your eyes wander, I will assume that you are cheating."
C. "I want to remind you of our rule to keep your eyes on your page."
D. "The last person who I caught cheating got an F for the exam and failed the course."