Costs which are proportionately responsive to changes in volume are:

The correct response to the question about costs that are proportionately responsive to changes in volume is variable costs. These costs fluctuate directly with the level of production or sales volume. For instance, in a food service operation, the costs of ingredients and raw materials are considered variable because as you prepare more meals, the total cost for food will increase as well. Conversely, if the volume decreases, these costs will also decrease.

Understanding variable costs is crucial for budget planning and cost control within nutrition and healthcare services, as they impact overall profitability based on service levels. This knowledge enables dietitians and health administrators to make informed decisions about resource allocation and operational efficiency.