The following data are the actual results for Marvelous Marshmallow Company for October. Actual output Actual variable overhead Actual fixed overhead Actual machine time 12,000 cases $409,000 $172,000 40,500 machine hours Standard cost and budget information for Marvelous Marshmallow Company follows: Standard variable-overhead rate Standard quantity of machine hours Budgeted fixed overhead Budgeted output $ 10.00 per machine hour 3 hours per case of marshmallows $168,000 per month 14,000 cases per month Required: Use any of the methods explained in the chapter to compute the following variances. (Indicate the effect of each variance by selecting "Favorable" or "Unfavorable". Select "None" and enter "O" for no effect (i.e., zero variance).) a. Variable-overhead spending variance b. Variable-overhead efficiency variance c. Fixed-overhead budget variance d. Fixed-overhead volume variance