Benjamin Inc. uses a standard cost system and has the following information regarding the labor and overhead used in the production of widgets. Standard labor input is 2.00 hours per unit. The variable overhead rate is $8.1 per hour; fixed overhead is budgeted to be $100,000 on budgeted production of 7,960 widgets. During August, Benjamin Inc. paid its workers $160,900 for 16,800 hours. Actual variable overhead incurred totaled $135,150, actual fixed overhead totaled $91,156. Benjamin Inc. produced 8,550 widgets during August. a. Calculate the variable overhead rate variance. (Do not round your intermediate calculations. Indicate the effect of variance by selecting "Favorable", "Unfavorable", or "None" for no effect (i.e., zero variance).) b. Calculate the variable overhead efficiency variance. (Indicate the effect of variance by selecting "Favorable", "Unfavorable", or "None" for no effect (i.e., zero variance). Round your answer to nearest whole dollar amount.) c. Calculate the fixed overhead spending variance. (Indicate the effect of variance by selecting "Favorable", "Unfavorable", or "None" for no effect (i.e., zero variance).)