The following labor standards have been established for a particular product Standard labor-hours per unit of output 8.6hours Standard labor rate $ 12.40per hour The following data pertain to operations concerning the product for the last month: Actual hours worked Actual total labor cost Actual output $ 6400hours 76,800 850units What is the labor efficiency variance for the month? $10.920 F $13,844 F $13.844 U $11.284 F