While Taking a Calculus Exam, Lindsey Got Stuck on a Certain

While taking a calculus exam, Lindsey got stuck on a certain question. She thought she had the right answer, but when she did a proof to check it, she realized she had made an error. She tried reworking it a few different ways, but she couldn't come up with the correct answer. Now she realizes that she's running out of time to finish the exam. What should Lindsey do?

A) Circle the question and move on to the next one.
B) Continue working on the question until she figures out the answer.
C) Cross the question out and move on to the next one.
D) Make a note in the margin to look up the answer after the test.