The Night Before a Midterm Exam, You Decide to Go

Multiple Choice

The night before a midterm exam, you decide to go to the movies instead of studying for the exam. You score 60 percent on your exam. If you had studied the night before, you'd have scored 70 percent. What was the opportunity cost of your evening at the movies?

A) 70 percent
B) 60 percent.
C) 10 percent off your grade.
D) Zero.