The following labor standards have been established for a particular product: Standard labor hours 8.1 hours per unit of output Standard labor rate $ 14.40per hour The following data pertain to operations concerning the product for the last month: 8,700hours 129,195 1,000 units Actual hours worked Actual total labor cost Actual output What is the labor rate variance for the month? $3,915 U $450 U $3,915 F $450 F