Marginal cost is defined as / » Fundamentals of Economics solved MCQs / By admin Question: Marginal cost is defined as A. the change in total cost due to one unit change in output. B. the change in total cost due to one unit change in input. C. the ratio of total cost to total output D. the ratio of total cost to total input Answer» a. the change in total cost due to one unit change in output. Note: The above multiple-choice question is for all general and Competitive Exams in India.