Marshall Industries gathered the following information for the month ended June 31: The static budget volume is 5,000 units. Overhead flexible budget: Number of units 10,000 11,000 12,000 Standard machine hours 14,000 15,400 16,800 Budgeted variable overhead costs: $63,000 $69,300 Budgeted fixed overhead costs: $16,800 $16,800 $75,600 $16,800 Actual production was 12,500 units. Actual overhead costs were $27,000 for variable costs and $36,000 for fixed costs. Actual machine hours worked were 17,000 hours. What is the standard variable overhead rate per machine hour? A. $1.09 O B. $6.30 C. $4.50 D. $4.13