Calculator The level of inventory of a manufactured product has increased by 8,123 units during a period. The following data are also available: Variable Fixed Unit manufacturing costs of the period $14.00 $3.00 Unit operating expenses of the period 1.00 4.00 The effect on operating income if variable costing is used rather than absorption costing would be an) Ca. $56,861 decrease b. $24,369 increase c. $24,369 decrease d. $56,861 increase