The level of inventory of a manufactured product has increased by 5,000 units during a period. The following data are also available: The effect on operating income if variable costing is used rather than absorption costing would be a a. $65,000 decrease b. $50,000 decrease c. $50,000 increase d. $65,000 increase The level of inventory of a manufactured product has increased by 5,000 units during a period. The following data are also available: The effect on operating income if variable costing is used rather than absorption costing would be a a. $65,000 decrease b. $50,000 decrease c. $50,000 increase d. $65,000 increase