I'm going to take a multiple choice exam
Why are you taking a multiple choice exam?
I need to prove that I can do well on the test.
Study hard and you'll do well. Good luck!
I will, but I'm going to use the answer key to cheat.
Cheating on an exam is a bad idea. Especially because if you're copying off the answer key there's a good chance you'll get caught. You should study instead!