Nuthatch Corporation began its operations on September 1 of the current year. Budgeted sales for the first three months of business are $260,000, S350.000, and $400,000, respectively, for September, October, and November. The company expects to sell 30% of its merchandise for cash. Of sales on account. 80% are expected to be collected in the month of the sale, 20% in the month following the sale, and the remainder in the following month. The cash collections in September from accounts receivable are: $145, 600 $223, 600 $192,000 $168,000 Which of the following costs is a mixed cost? Salary of a factory supervisor Electricity costs of $2 per kilowatt-hour Rental costs of $5,000 per month plus $.30 per machine hour of use Straight-line depreciation on factory equipment