Complex Company has the following estimated costs for next year: Direct materials $15,000 Direct labor $55,000 Sales commissions $75,000 Salary of production supervisor $35,000 Indirect materials $ 5,000 Advertising expense $11,000 Rent on factory equipment $16,000 Complex estimates that 15,000 direct labor and 20,000 machine-hours will be worked during the year. If overhead is applied on the basis of machine-hours, the predetermined overhead rate per hour will be: a. $6.30 b. $10.60 c. $7.10 d. $2.80 e. $3.73 Please kindly show me step by step calculations