Below is the net income of Oriole Instrument Co., a private corporation, computed under the three inventory methods using a periodic system. FIFO Average Cost LIFO 2018 $26,400 $23,100 $20,900 2019 27,000 22,200 17,200 2020 27,500 25,700 22,100 2021 32,800 29,100 24,400 (Ignore tax considerations.) (a) Assume that in 2021 Oriole decided to change from the FIFO method to the average-cost method of pricing inventories. Prepare the journal entry necessary for the change that took place during 2021, and show net income reported for 2018, 2019, 2020, and 2021. (Credit account titles are automatically indented when amount is entered. Do not indent manually. If no entry is required, select "No Entry for the account titles and enter O for the amounts.) Account Titles and Explanation Retained Earnings Inventory Debit Credit 9900 9900 Net income 2021 2020 2019 2018