Choice "C" is correct. Relevant range is the range of activity within which the relationships of fixed costs and variable costs are meaningful and valid.
Choice "a" is incorrect. Theoretical maximums and minimums may have nothing to do with actual operating characteristics of a given firm.Choice "d" is incorrect. For most companies, costs fluctuate over the entire range of operations.Choice "b" is incorrect. Costs are incurred at every possible operating point.
