In the Navy, we take exams for rank advancement -- we have a phrase. When in doubt, Charlie out. In other words, if you don't know, guess C and move on
In my AP European History class in high school, we had a 25 question quiz the next day every time we were assigned a chapter to read in the textbook (maybe once every week or two). They were intentionally difficult to try to encourage us to read closely, often asking about specific details that were only mentioned once in the chapter, and they were heavily curved, so getting even around half of the questions right generally would get you a decent grade. The teacher had a habit of making the last choice of each question be a combination of two of the earlier choices (e.g. "both A and C"), and these often ended up being the right answer to the point where one of my classmates came up with the idea of choosing the last choice in every single question to try to get an easy passing score. Unfortunately for him, he was a bit too proud of this idea and talked about it enough beforehand that the teacher caught wind of it and purposely made none of the answers on the next quiz have the last choice be correct. Not sure how well that would go over in the Navy, but I'd certainly still be a bit worried that the exam writer might know the rule of thumb people use and have a bit of fun at my expense!
> Or maybe it's just that you need to pick something, so why not C?
Mostly this. That said, one definitely picks up when teachers bias the dice.
Some want an even distribution. If you confidently answered C's and D's early on and were later forced between A and C, A was the lucky bet. Other teachers avoided the first and last choices like the plague; this was common. With them, B and C (on a four-choice test) were the lucky bets.
Well with a sample size of one the 2022 test had 9/24 the answers as C which is above an expected (6/24) 25%.
Definitely some of the more annoying tests I've taken were when the answers were the same over and over. Its so weird to answer a T/F as T 10 times in a row and I've definitely lost points because I changed some of my Ts to Fs because I thought there was no way it was all Ts.