The level of inventory of a manufactured product has increased by 6,981 units during a period. The following data are also available: Variable Fixed Unit manufacturing costs of the period $12.00 $6.00 Unit operating expenses of the period 1.00 The effect on operating income if absorption costing is used rather than variable costing would be a 4.00 a. 569,810 increase b. $41,886 decrease c. $69,810 decrease d. 541.686 increase