it says "what is the chance you will be correct?" It must be 0% since there are no correct answers.
To choose a random answer out of 4, you have a 25% chance to get a correct answer.
25% is the answer, but since there are two 25% choices...both of them are correct...
so you have 2 correct answers to 2 wrong answers... you have 50% chance of getting correct...
...right?