Use the Following to Answer Questions

Multiple Choice

Use the following to answer questions:
-(Table: Variable Costs for Lawns) Look at the table Variable Costs for Lawns. During the summer, Alex runs a lawn-mowing service, and lawn-mowing is a perfectly competitive industry. Assume that costs are constant in each interval; that is, the variable cost of mowing 1 through 10 lawns is $100. His only fixed cost is $1,000 for the mower. His variable costs include fuel, his time, and mower parts. If the price for mowing a lawn is $70, how much is Alex's profit per unit at the profit-maximizing output?

A) -$10
B) $10
C) $34
D) $14