Now try to answer this question before reading any further. Then scroll down.

Remember that opportunity cost refers to a choice you could have made but which was precluded by the actual choice. For part "a", this could be the potential earnings you gave up when you decided to attend college, especially if you are a full-time student. If you are taking courses part-time, then the opportunity cost might involve giving up spending additional time with your family or giving up the possibility of working a second job.

For part "b", perhaps you gave up the opportunity to take a different course, possibly one that was of greater interest to you. You may be taking this course to satisfy a curriculum requirement even though you’re not particularly interested in it. (We’ll try to change that, though!)

In part "c", you may have forgone the opportunity to prepare or do coursework for another class or perhaps you could have gone home early for some rest and relaxation.

Your own answers could very well differ from these because opportunity costs will vary from person to person. Now that you know something about implied costs you may be more conscious of them as you go about your daily activities.