The answer changes depending on how far you take it. It will always be either 25% or 50% depending on on which step of the overthinking process you're on.
At first glance, its 25% since theres 4 possible answers.
But two of them give the same correct answer, which changes the answer to 50%
Upon a third look, you see that since the answer is 50%, that the two 25% answers are no longer correct, which drops the odds back down to 25%.
Then you're back at the first step, because 25% is once again the correct answer. But there are two 25% options, which raises the odds back up to 50%.
Congratulations, you've created a paradox

.
So really, there is no answer. 25% is wrong, 50% is wrong, 66% is wrong, and so is 0%, as well as 33.3(1/3)%. This is an example of something that is mathematicaly impossible, but that should have an answer if only you can work your way through it. Mathematicians will probably create another imaginary number, similar to
i because they can't accept that some things just don't have an answer.
You've just screwed over the future school children by creating something new, irrelevent, and completly useless in all real world applications for them to learn.