The following labor standards have been established for a particular product: Standard labor-hours per unit of output Standard labor rate 8.1 hours $14.40 per hour The following data pertain to operations concerning the product for the last month: Actual hours worked Actual total labor cost Actual output 8,700 hours $129,195 1,000 units What is the labor efficiency variance for the month? What is the labor efficiency variance for the month? Multiple Choice o $8640U $8,640 0 o S12 555 U o S12 555 F o $8,910 U