Use the Following to Answer Questions

Multiple Choice

Use the following to answer questions:
-(Table: Variable Costs for Lots) Look at the table Variable Costs for Lots. During the winter, Alexa runs a snow-clearing service in a perfectly competitive industry. Assume that costs are constant in each interval; that is, the variable cost of clearing anywhere from 1 through 10 lots is $200. Her only fixed cost is $1,000 for a snowplow. Her variable costs include fuel, her time, and hot coffee. If the price to clear a lot is $60, what is Alexa's profit per unit at the optimal output?

A) $60
B) $42
C) $35
D) $18