The level of inventory of a manufactured product has increased by 7,000 units during a period. T Unit manufacturing costs of the period Unit operating expenses of the period Variable Fixed $12.00 $6.00 4.00 1.50 The effect on operating income if absorption costing is used rather than variable costing would be a a. $52,500 increase b. $42,000 increase Oc. $52,500 decrease Od. $42,000 decrease