Nah it's a paradox. There's no such thing as just a freestanding Monte Carlo test that you can just "run" - you do actually need to define enough parameters to make it tell you anything.

This kind of self-referential stuff feels like a proof of Gödel's incompleteness theorems with extra steps.

The trick is that there is no paradox, only the implication of one. 'If' being the key word - you're not actually being asked to answer randomly, but you are being subtly trolled.

If you ignore self-referential nature of the question and stop the iteration at some point, sure, you can argue that any answer is correct.

If you ran a infite monte carlo test on it, you’d end up with 0% correct answers.

That would mean your Monte Carlo test is set up incorrectly because at least 1/4 of the results of the test would be the "correct" answer as per your own argument, thus invalidating it.

Yeah, that's me. They're ready.

It's actually 2S with S=12.5

It's a mimic-dark souls math. If you pick it, the test eats you.

A crocodile has your toddler. It says it will return your child if you can guess its next move. What do you say?

The question is not asking you to pick at random. It's asking you to suppose that you do pick at random and to mark the correct answer not at random.

If "no answer" is in the set of possible answers, then it is not a correct answer because there's then a 20% chance of it being picked at random. But usually that's not the case for tests anyways.

Severe programmer mentality 😂 I like it, but I doubt it would play out in the real world

They aren't asking them to pick an answer at random though.

This is the only correct answer to the question as stated.

That of course opens a second can of worms, since now you are actually forced to "pick the answer at random", now with the probability of 50%. But such double entendres are typically not considered for test questions unless explicitly specified.

What coin do you have with 4 sides

I've never heard that rule. It sounds like an assumption you're making about the question!

If the answer is B, that means there's a 25% chance of getting the right one. So the answer is A and D. But wait... that's 50%

50% means 25%

That means 50%

So it's 0% because it's impossible.

Meaning it's 25%

Damn it

Not really but you're thinking in the right direction!

There is no correct answer because the question and the answers exclude themselves:

For four different options it is 25% but here two options are the same - so you have a 50% chance to land on a 25% - but this means that the correct answer is only in one of the four answers, therefore you're having a 25% chance.

It's a nice demonstration of what happens when the answer and question are intervined and any result changes an aspect of the answer - you're fucked, basically.

You can’t separate the question like that. Whichever answer you circle indicates your assertion that this is the probability of getting the correct answer by uniform random chance.

This means that any answer you circle is wrong, and so the correct answer is to not circle any of them. You could even write e) none of the above to indicate that you have deliberately chosen not to circle one of them instead of skipping the question.

I have had plenty of exams with multiple choice questions that included the possibility of no correct answers, one correct answer, or even multiple correct answers, and we were expected to make that judgement (rather than blindly follow instructions).

It’s definitely B ) 50%. Ignoring the values for answers, there can only be 1 “correct” answer. If you have 4 options and 1 can be correct, a random guess is 25%. Since there are 2 options for 25%, you have a 50% chance of guessing the correct 25%.

Mixed?

Not quite. All information is present, but the answer changes in a way that makes this unanswerable.

If it's a part of the standardized test that actually does make it much easier. A standardized test only allows to mark one option and that option needs to be derived unambiguously from the question. As such, neither A nor B are actually possible answers under this framework, D is not a possible answer to the question, and we're left with C.

If I was given the original question as part of some standardized test, I would probably think about it for a while, flip a coin mentally, choose either A or D, and then contest it afterwards if it gets marked as being incorrect.

Still too hard. I'll take the 50/50 joker. Which answers remain?