The level of inventory of a manufactured product has increased by 7,607 units during a period. The following data are also available: Variable Fixed Unit manufacturing costs of the period $11.00 $5.00 Unit operating expenses of the period 1.00 3.00 The effect on operating income if variable costing is used rather than absorption costing would be an) a. $38,035 decrease b. $60,856 decrease c. $60,856 increase d. $38,035 increase