P11-1 Calculating Costs and Break-Even [LO3] Night Shades Inc. (NSI) manufactures biotech sunglasses. The variable materials cost is $1.35 per unit, and the variable labor cost is $1.89 per unit. a. What is the variable cost per unit? b. Suppose the company incurs fixed costs of $510,000 during a year in which total production is 229,500 units. What are the total costs for the year? c. If the selling price is $10.45 per unit, what is the NSI break-even on a cash basis