Clearly, the strict policy adopted by prestigious Central

Clearly, the strict policy adopted by prestigious Central University against cheating has worked. Since the university implemented its "no tolerance for cheating" policy two years ago, no student has dared to risk the harsh consequences for cheating. Central University has threatened to immediately shut down all competitive athletic activities if any student is caught cheating on an exam. Because students don't want to incur the wrath of the university and their fellow students, no has been caught cheating on an exam since the policy was implemented. This proves that the policy works.

Which of the following selections points out a flaw in the author's reasoning?
(a) Central University's athletic programs account for a significant percentage of the university's annual budget.
(b) Considering the problems Central University experienced in the years preceding the "no tolerance for cheating" policy, it is impossible to predict that students will never again cheat on exams at Central University.
(c) A teacher could accuse a student of cheating who is innocent, for instance, if a student's examination on computer disk was inadvertently copied onto another student's disk during the grading process; this could trigger a shut-down of athletic activities.
(d) Students have cheated in more sneaky ways outside of classroom exams, for example, by students paraphrasing their classmates' book reports.
(e) It is impossible to tell whether cheating incidents disappeared due to another reason, i.e., perhaps teachers implemented classroom testing procedures which made it extremely difficult to cheat on classroom tests