After this lesson, you are given a multiple-choice exam. When you come to question five, you know that the answer is A or B, but can't decide which. You deliberate and finally choose A. You are sitting next to the hallway door, and when you are just about finished with the test, you hear one of your fellow classmates in the hallway remark, “Oh no, I thought for sure that the answer for question five was B,” which of course tells you that you choose the wrong answer. What do you do? ​