I see that there's still a lot of confusion as to why "D" is an incorrect option. Lets look at the two solutions we agree upon :-
Solution 1) The Vigilance/Officials are doing a better job of finding cheaters, hence higher # of cheaters brought to book, despite overall lower # of cheating students
Solution 2) Students provided false reports......
Although it seems like both the above solutions are "correct",
the 2nd solution above conflicts with the premise laid out in the question. The Premise uses the phrase
"students admitted to..." which we must take to mean they were honest while reporting.
If a GMAT option seems to be "going against the given premise", you can almost surely take that to be a trick option, trying to suck you into making a mistake! Vigilance is key here!

Now that you have these two solutions, would you not take the first solution, simply because it does not go against the premise?
Hope this helps! Sorry I didnt check this thread in a long time

, but I hope those who come along now will find it helpful. GMAT questions will not try to go against given premise, a very useful vigilance tool; Cheers.
- Vishnu
ronr34
I still don't get it.
If the students provided false reports, and they also did it in the past, that doesn't take away from the explanation.
As I see it, D settles the paradox.
Can anyone offer a different explanation?