please help with how to solve this thank you

This Company uses standard costing. Variable overhead is applied at $8 per direct labor hour. Data for the month of September follows: Actual overhead variable costs Standard hours allowed for actual production Actual labor hours worked $ 78,000 10,000 9,800 How much is the controllable overhead spending variance? a. $2,000 favorable b. $400 favorable c. $400 unfavorable d. $2,000 unfavorable

Need step by step answer