Requirement 4. Reconcile the operating incomes under variable costing and absorption costing for each year, and use this information to explain to the positive operating income in and the drop in operating income in . (Complete all input fields. Enter a "0" for any zero amounts. Use parentheses or a minus sign for negative differences.)\ Reconciliation of absorption/variable costing operating income\ 2019\ 2020\ 2021\ (1)\ Absorption costing operating income\ $0\ $324,800\ $40,600\ (2)\ Variable costing operating income\ 0\ 0\ 365,400\ (3)\ Difference (1) - (2)\ $0\ $324,800\ $(324,800)\ (4)\ Fixed mfg. costs in ending inventory (Absorption)\ $0\ $0\ (5)\ Fixed mfg. costs in beginning inventory (Absorption)\ 0\ 0\ \ (6)\ Difference (4) - (5)\ $0