Preble Company manufactures one product. Its variable manufacturing overhead is applied to production based on direct labor-hours and its standard cost card per unit is as follows: The planning budget for March was based on producing and selling 21,000 units. However, during March the company actually produced and sold 26,000 units and incurred the following costs: a. Purchased 160,000 pounds of raw materials at a cost of $6.50 per pound. All of this material was used in production. b. Direct laborers worked 70,000 hours at a rate of $16 per hour. c. Total variable manufacturing overhead for the month was $655, 200. What is the variable overhead efficiency variance for March