The level of inventory of a manufactured product has increased by 8,473 units during a period. The following data are also available: Variable Fixed Unit manufacturing costs of the period $12.00 $8.00 Unit operating expenses of the period 2.00 2.00 The effect on operating income if variable costing is used rather than absorption costing would be a(n) Oa. $84,730 decrease Ob. 567,784 decrease Oc. $67,784 increase Od. $84,730 increase