Which of the Following Is NOT an Example of Sexual

Which of the following is NOT an example of sexual harassment?

A) A university freshman seeks help from her male teaching assistant (TA) . After going over the course work, he suggests they go out to grab a bite to eat, indicating that her grades might improve if she got to know him better.
B) Upon a male student being late for class, a female professor quips in front of the entire class, "Perhaps you need to learn the art of quick love making."
C) A male student politely declines several requests of his female TA for a date. The female TA repeatedly sends email requests asking for a date, despite the male student repeatedly denying her requests.
D) All of the above are examples of sexual harassments.