The following labor standards have been established for a particular product: Standard labor-hours per unit of output Standard labor rate 5.0 hours $19.85 per hour The following data pertain to operations concerning the product for the last month: Actual hours worked Actual total labor cost 7.300 hours $148.190 1.400 units Actual output. What is the labor efficiency variance for the month? Select one: a. $9,240 F b. $9,240 U c. $5,955 U 0 d. $6,090 U