The correct answer is: "studying the profitability of growing apples versus oranges"
The opportunity cost is defined as the value of the rejected alternative when a producer, business, or investor chooses one option over another. The chosen alternative would be the one which carries the lowest opportunity cost.
In the example provided, if the producer discovers that the profitability of growing apples is larger, he would choose to produce apples. Then, the opportunity cost would be the amount of money that he could have gained from producing oranges.
