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Suppose that you are spending two hours a day studying economics, and your grade is 85 percent. You want a higher grade and decide to study for an extra hour a day. As a result, your grade rises to 90 percent. Your marginal benefit is the (假设你每天花两个小时学习经济学,你的成绩是85%。你想要一个更高的年级,并决定每天学习多一个小时。因此,你的成绩上升到90%。你的边际效益是——中文由在线翻译而来,仅供参考.下同.)
A.
5 point increase in your grade minus the opportunity cost to you of spending the hour studying.你的成绩增加5分,减去你花时间学习的机会成本。
B.
extra hour per day you spend on studying.每天花费额外的时间学习上。
C.
5 point increase in your grade.你的成绩提高5点。
D.
three hours per day you spend on studying.每天三个小时你学习上。