Machining 30,000 150,000 Assembly 40,000 200,000 Direct labor hours Machine hours Manufacturing overhead costs $600,000 $800,000 A predetermined manufacturing cost driver rate for the Machining Department based on the number of machine hours in that department is: Select one: A. $20 per machine hour. B. $10 per machine hour. C. $40 per direct labor hour. D. $ 4 per machine hour