In a production possibilities frontier (PPF), the slope indicates which of the following?

The slope of the production possibilities frontier (PPF) is a critical concept in economics because it represents the opportunity cost of producing one good over another. The PPF illustrates the maximum possible output combinations of two goods that can be produced given limited resources and technology. As you move along the curve, to increase the production of one good, you must decrease the production of another.

This trade-off is quantified by the slope of the PPF, which signifies how much of one good must be forgone to produce an additional unit of the other good. Therefore, the steeper the slope, the higher the opportunity cost of switching production from one good to another. Conversely, if the PPF is relatively flat, the opportunity cost of making that switch is lower. Thus, the slope directly reflects the concept of opportunity cost, making it the correct answer.

The other options do not accurately represent what the slope of the PPF conveys. Average cost of production pertains to how much each unit costs to produce, which is a different concept altogether. Profitability relates to the earnings from production compared to its costs, while total cost accounts for all expenses involved in production, neither of which can be directly derived from the slope of the PPF.