This can also be used a great example of proof by contradiction: There is no correct answer in the options. Proof: Assume there was a correct answer in the options. Then it must be either 25%, 50% or 60%. Now we make a case distinction.

(A) Assume it was 25. Then there would be two of four correct options yielding in a probability of 50%. Therefore 50 must be the correct answer. -> contradiction.

(B) Assume it was 50. Then there would be one of four correct options yielding in a probability of 25%. Therefore the answer is 25. -> contradiction.

(C) Assume it was 60%. Since only 0,1,2,3 or 4 of the answers can be correct the probability of choosing the right answer must be one of 0% 25% 50% 75% or 100%. -> contradiction.

Because of (A), (B) and (C), it cannot be 25, 50% or 60%. -> contradiction.

You can never answer this question correctly. If the correct answer is 25% there's a 50% chance you guess correctly but that would make the 25% wrong.

But if the answer is the 50% then it implies that 25% is correct which implies that 50% is wrong.

We reach a contradiction for both 25% and 50% making the correct answer to make the whole statement truthy 0%.

0%

The only winning move is not to choose

Thanks for making me laugh all alone in my car before heading in to work. I wish I could give you an award. Cheers!

If you're choosing the answer, then there is 100% chance of being correct. Since none of these answers is 100%, the chance is 0%.

It was only the next day that I returned to this post realising that "this question" isn't even defined.

What's the correct value if the answer is not picked at random but the test takers can choose freely?

33% innit

Any answer is correct as long as you don't pick it at random. I'd choose (a) because I'm too lazy to read the other options

I would think a b c d so 25% O he made a mistake znd forgot to take the bubble answer out. Now we only can pick between aord b c so it would be 33%

Seems my logic is wrong iff i read the rest

The answer is clear

I choose 75%

Great! I'll hand this to my daughter to annoy her co-students who struggle with probabilitiy ;-)