Preble Company manufactures one product. Its variable manufacturing overhead is applied to production based on direct labour-hours, and its standard costs per unit are as follows: Direct materials: 4 kg at $9.00 per kg Direct labour: 3 hours at $15 per hour Variable overhead: 3 hours at 56 per hour Total standard cost per unit $36.00 45.00 18.00 $ 99.00 The company planned to produce and sell 26,000 units in March. However, during March the company actually produced and sold 31,000 units and incurred the following costs: a. Purchased 155,000 kg of raw materials at a cost of $720 per kg. All of this material was used in production b. Direct labour: 56,000 hours at a rate of $16 per hour. Total variable manufacturing overhead for the month was $524720 8. What is the variable overhead rate variance for March? (Round the actual overhead rate to two decimal places. Indicate the effec of each variance by selecting "F" for favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance...)