please include work, i would like to understand. thank you!

Machine Builders Incorporated adopted a standard cost system several years ago that it uses in conjunction with its process cost system. The per-unit standard costs for direct materials and direct labor for its single product are as follows: Materials: (4 kilograms x $10 per kilogram) Labor: (4 hours * $18 per hour) $ 40 $ 72 All materials are issued at the beginning of processing. The operating data shown below were taken from the records for July In-process beginning inventory In-process ending inventory-90% complete as to labor Units completed during the month Budgeted output Purchases of materials, in kilograms (AQ) Total actual labor costs incurred Direct labor hours worked (AQ) Materials purchase-price variance Increase in materials inventory in July Beginning inventory of materials none 2,900 units 8,910 units 9,900 units 41,400 $ 762,500 38,640 hours $ 4,140 unfavorable 2,070 kilograms 0 kilogram The direct labor flexible-budget variance for July was: The direct labor flexible-budget variance for July was: Multiple Choice O $59,740 favorable. O $15,940 unfavorable. 0 $74,140 favorable. O $66,940 favorable. O $15,340 unfavorable