问题详情

Julie plans to sell delicate paper boxes in her retail shop. The selling price is ＄10, while the cost is ＄5 per unit. The fixed costs she encounters will be ＄600. Then the breakeven is ______.
A．40 units.
B．60 units.
C．80 units.
D．120 units.请帮忙给出正确答案和分析，谢谢！