There is a popular question, called "Best statistics question ever".

If you choose an answer to this question at random, what is the chance you will be correct?

A) 25%
B) 50%
C) 60%
D) 25%

This task is not very difficult, the correct answer is 0%. But if we modify it like this:

If you choose an answer to this question at random, what is the chance you will be correct?

A) 50%
B) 25%
C) 60%
D) 50%

What will be the correct answer? Do we have two correct answers: 25% and 50%, or there is no correct answer, as with this two correct answers the chance of choosing the correct answer is in fact 75% (but we do not have 75% written on the desk)?

By the way. Does the answer 0% remains correct answer, the third correct answer in this case?