The level of inventory of a manufactured product has increased by 7,742 units during a period. The following data are also available: Variable Fixed Unit manufacturing costs of the period $10.00 $7.00 Unit operating expenses of the period 2.00 The effect on operating income if variable costing is used rather than absorption costing would be an) Oa. $54,194 increase Ob. 569,678 decrease Oc. 569,678 increase Od 554,194 decrease 2.00