For Her Senior Thesis, Nancy Surveys Fellow Students About Cheating

For her senior thesis, Nancy surveys fellow students about cheating. Her findings suggest that cheating is virtually non-existent on her campus. This is not consistent with the fact that, in the past semester, two dozen students have been found guilty by the Honor Board of cheating. Which of the following explanations would fall under the heading of "reactivity?"

A) Nancy's data were a "one shot" picture, and therefore could not be too accurate
B) the questions on Nancy's survey probably were not phrased well enough to collect accurate data
C) it is known that participants in research like to present themselves as positively as possible, so students that cheated probably lied and did not report their cheating on the survey
D) Nancy's survey was confounded by being too demanding