Economically speaking, I'd like to trade my study for an A

Tomorrow morning is the first economics exam. After last night’s assignment, my overall grade in the class rose to 99.1%, which to me means I have learned the material and handled it well enough to be eligible for an A on the test. I studied for a few hours tonight, reviewing forgotten principles and their applications. I looked through the entire first four chapters of the textbook, and I feel confident that I know what should be on the test. Still, I don’t like the fact that the instructor himself said his exams are difficult and that the average grade on them is usually a D. At this point, I stay confident that I've done my best, and I do my best tomorrow.