Walsh Corporation uses a job-order costing system with a single plantwide predetermined overhead rate based on machine-hours. The company based its predetermined overhead rate for the current year on the following data: Total machine-hours Total fixed manufacturing overhead cost Variable manufacturing overhead per machine-hour 30,000 $ 252,000 $ 2.10 Recently, Job T687 was completed with the following characteristics Number of units in the job Total machine-hours 30 Direct materials $ 675 Direct labor cost $ 1,050 The predetermined overhead rate is closest to: Select one: a. $10.50 per machine-hour b. $8.40 per machine-hour c. $2.10 per machine-hour d. $12.60 per machine-hour