The level of inventory of a manufactured product has increased by 5,000 units during a period. The following data are also available: Variable Fixed Unit manufacturing costs of the period $24.00 $10.00 Unit operating expenses of the period 8.00 3.00 The effect on operating income if variable costing is used rather than absorption costing would be a O . $65,000 decrease b. $65,000 increase c. $50,000 increase Od. $50,000 decrease