The level of inventory of a manufactured product has increased by $7,774$ units during a period. The following data are also available:Line Item DescriptionVariableFixedUnit manufacturing costs of the period$$12\mathrm{.}00$ $$3\mathrm{.}00$ Unit operating expenses of the period$2\mathrm{.}005\mathrm{.}00$ The effect on operating income if variable costing is used rather than absorption costing would be a$($n$)$a$.$ $$62,192$ decreaseb. $$23,322$ increasec. $$23,322$ decreased. $$62,192$ increase