1. In each of the following situations, identify which of the twelve principles is at work

a) You choose to purchase your textbooks online through Chegg rather than paying a higher price for the same

books through your college bookstore.

a. The true cost of something in its cost of opportunity

Explanation:

Opportunity cost is the cost which is defined as the cost or expense of one item which is lost in order to get the opportunity to do or to consume something else. In simple words, it is the value or the cost of the next best available alternative.

So, when the person select to bought the textbooks through Chegg instead paying the higher price for the same books through the bookstore. Under this situation, the principle applies is the cost of something in its opportunity cost.