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: Direct materials: 5 pounds at $10 per pound $ 50 Direct labor: 3 hours at $17 per hour 51 Variable overhead: 3 hours at $7 per hour 21 Total standard cost per unit $ 122 The planning budget for March was based on producing and selling 24,000 units. However, during March the company actually produced and sold 30,600 units and incurred the following costs: a. Purchased 170,000 pounds of raw materials at a cost of $9.00 per pound. All of this material was used in production. b. Direct laborers worked 68,000 hours at a rate of $18 per hour. c. Total variable manufacturing overhead for the month was $512,040. What is the labor rate variance for March?