Concept:Total cost is the sum of all costs incurred in production, combining fixed and variable costs.
Explanation:In the cost graph, R is the total cost curve. It starts at the level of fixed cost and rises as output increases.
This is because total cost includes both variable and fixed cost:
TC=TFC+TVCMarginal cost is the extra cost of producing one more unit, so it is not represented by R.
Variable cost starts from zero, while fixed cost remains constant at all output levels. Therefore, R cannot be variable or fixed cost alone.
Hence, the curve labelled R is the total cost curve.
Answer:B. total cost
