Exactly. So the probabiity of choosing the correct answer epended on which answer you chose, and when chosen, the answer would be different. That's why 0% was the actual probability with the original choices - you're fucked no matter what.
Paul's option wasn't really any better!
Unfortunately, mine works, which makes it much less entertaining. Until you grade them, that is. then you find that less than 25% will get the right answer - generally, students do worse than random on probability questions!
I really hate multiple guess questions...