Harris Enterprises machines heavy duty brake rotors that are used on commercial airliners. The company's management developed the following standard costs: Standard direct labor hours per rotor 1.6 Standard overhead rate per direct labor hour $11.25 Actual activity for October Actual overhead costs incurred Actual direct labor hours Actual rotors machined $148.200 11,400 4.300 What is the total variable manufacturing overhead varlance in October? A. 599.825 favorable OB. $99.825 unfavorable C. 570,800 favorable OD. 570.800 unfavorable