4. Standard cost svstem labor variance The following computations of March labor variances for Sam's Supply Company are incomplete. The missing items are labeled (a) through (d). Labor rate variance = 4.800 hours x [(a)-$8.50-$350 favorable Labor efficiency variance = (b) x [(e)-5,000 hours-$() On the appropriately labeled line, identify each missing item by name (a through e) and show the missing value (a through d). Show supporting computations in the space provided. hours (d) S F or U [Choose the correct term.] e) During March, the supervisor left for vacation without arranging for a replacement. Which variances would have been most affected by this situation? Computations