Carla Sells Hot Coffee, Cider and Tea from a Sidewalk

Carla sells hot coffee, cider and tea from a sidewalk cart near Wall Street in New York City. Last month she sold $4,500 worth of product to 1,000 customers. She spent $800 on buying her beverages in bulk. Her monthly costs are: Utilities = $100, Salary = $2,000, Advertising = $0, Insurance = $0, Interest = $0, Rent (cart) = $600, Depreciation = $0. Calculate Carla's average sale per customer.

A) $5.00
B) $4.00
C) $4.50
D) $4.67