The level of inventory of a manufactured product has increased by 8,586 units during a period. The following data are also available: Variable Fixed Unit manufacturing costs of the period $10.00 $4.00 Unit operating expenses of the period 3.00 2.00 The effect on operating income if absorption costing is used rather than variable costing would be a a. $51,516 increase b. $34,344 increase c. $51,516 decrease d. $34,344 decrease