Single Company has a standard cost system in which manufacturing overhead is applied to units of product on the basis of standard direct labor-hours. The company has provided the following data concerning its manufacturing overhead costs for last year: Standard direct labor-hours allowed for the output......... Actual direct labor-hours worked........... Denominator activity....... Actual variable factory overhead cost. Variable overhead rate....... The variable overhead efficiency variance would be: Select one: O a. $10,000 U O b. $5,000 F O c. $15,000 U O d. $5,000 U 32,000 hours 33,000 hours 30,000 hours $166,000 $5 per hour