Marigold Corp. sells its product for $80 per unit. During 2019, it produced 60000 units and sold 50000 units (there was no beginning inventory). Costs per unit are: direct materials $20, direct labor $12, and variable overhead $1. Fixed costs are: $720000 manufacturing overhead, and $90000 selling and administrative expenses. The per unit manufacturing cost under variable costing is:_____.a. $32. b. $33. c. $47. d. $45.