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: 4 pounds at $9 per pound Direct labor: 3 hours at $15 per hour Variable overhead: 3 hours at $6 per hour Total standard cost per unit $ 36 45 18 $ 99 The planning budget for March was based on producing and selling 26,000 units. However, during March the company actually produced and sold 31,000 units and incurred the following costs a. Purchased 155,000 pounds of raw materials at a cost of $7.20 per pound. All of this material was used in production b. Direct laborers worked 56,000 hours at a rate of $16 per hour. C. Total variable manufacturing overhead for the month was $524,720. . What is the labor efficiency variance for March? (Indicate the effect of each variance by selecting "F" r favorable, "U" for unfavorable, and "None" for no effect (i.e., zero variance.) Input all amounts as ositive values. Do not round intermediate calculations.) Answer is complete but not entirely correct. abor efficiency variance $ 666,000 F