The following standards for variable overhead have been established for a company that makes only one product The following data pertain to operations for the last month: Required: a. What is the variable overhead rate variance for the month? b. What is the variable overhead efficiency variance for the month? Note: Indicate the effect of each variance by selecting "F" for favoroble, " U " for unfovorable, and "None" for no effect (i.e., zero variance). Input all amounts as positive values