Final answer:
The margin of safety is the extent to which the planned volume of sales lies above the break-even point, offering a buffer against sales fluctuations and aiding in long-term production planning.
Step-by-step explanation:
The margin of safety is best described as C. The extent to which the planned volume of sales lies above the break-even point. The margin of safety indicates how much sales can fall before a business reaches its break-even point, where total revenues equal total costs (both fixed and variable). It provides a buffer for a business against sales fluctuations, allowing for better planning and risk management. The formula given in option D is used to calculate the break-even point rather than the margin of safety itself. Understanding the margin of safety can be crucial for long-term production planning and establishing a profit-maximizing strategy.