Final answer:
Marginal revenue is correctly calculated as the A. change in total revenue divided by the change in the quantity sold, which is option A among the provided choices.
Step-by-step explanation:
The calculation of marginal revenue can be determined by analyzing how changes in revenue correlate with changes in the quantity sold.
According to the information provided, the correct way to calculate marginal revenue is A. Change in total revenue divided by change in quantity.
This represents the additional income a firm receives when it sells one additional unit of a good or service.
It is not the change in quantity divided by change in total revenue, total revenue divided by quantity, or change in total cost divided by change in quantity.
These other formulas are used for calculating different economic metrics such as average revenue and marginal cost.