If you choose the incorrect answer on BR that means you need to go back and review that question - there is a good chance that either you are second-guessing yourself too much, or you may have an issue with the underlying content of the question.
I hate to be the bearer of bad news, but I think the curve for this test was determined like over 3 years ago and not on the distribution of how the collective test takers did today. Please correct me if I'm wrong.