Final answer:
The break-even sales level requires the contribution margin per unit, which cannot be calculated without knowledge of variable costs. As this information is not provided in the question, we cannot determine the break-even sales level.
Step-by-step explanation:
The question asks for the break-even sales level of a firm which can be calculated using information about the firm's fixed costs, operating profit, and unit sales. Given an operating profit of $15,000 with unit sales of 10,000 units and fixed costs of $30,000, we can determine the contribution margin per unit and then find the break-even point.
To calculate the contribution margin per unit, we need to know the variable costs, which can be derived from the given operating profit and unit sales. The operating profit is the excess of total revenues over total costs (fixed costs plus variable costs). With given fixed costs, we can determine the contribution margin, which then leads us to break-even sales volume. However, the variable costs per unit are not provided, and this information is crucial for determining the contribution margin and calculating the break-even point. Without it, we cannot accurately answer the question. Therefore, the correct option is D. There is not enough information to determine the unit break-even point.