[ProtegeManiac]

Once, in secondary school, I was running a high enough average in a particular class that I'd pass regardless of how well I did on the final. So I answered B for all 100 questions, and to the consternation of the teacher left for the day after 6 minutes. As precisely 40 answers were B, I got a 40.

 

If I was running a high enough average, I'd be worried about ruining that high average just as much as I would have been if I was in danger of failing. 

 

In the high school there was barely any such thing as "best screw this" guesses. For one, many multiple choice tests don't have a 1/4 probability - ours was often 1/5 especially for the finals. Sometimes E was all or none of the above; other times, D was "all" and E was "none." And then sometimes they make sure every other answer was partially correct; but in math, they deliberately compute with errors and use the ones that seem like the most common ways of getting it wrong. 

Past that, the multiple choice part was only around 50% of the exams - the other 50% were essay questions, or longer, tear-your-hair-out during or pass-the-paper-then-realize-you-screwed-up math problems. We try not to look at our scratch papers after the test and just toss 'em (if the tests weren't synchronized the teachers will take the scratch papers) despite the fact that we are advised to review them to see where we went wrong, because at one point a friend did that right after the test, saw his error, and HE ATE HIS DAMN SCRATCH PAPER right there on the hallway.