Carla Vista's Nursery provides and maintains live plants in office buildings. The companys 140 customers are charged $190 per month for this service, which includes weekly watering visits. The variable cost to service a customer's location is $42 per month. The company incurs $4,000 each month to maintain its equipment and service vans and $5,000 each month in salaries. Carla Vista pays a CPA firm $25 per customer for accounting services. (a) Prepare Carla Vista's contribution formst incone statement for the month