Below is the net income of Shamrock Instrument Co. a private corporation, computed under the three inventory methods using a periodic system. (ignore tax considerations) (a) Assume that in 2021 Shamrock 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 tittes and enter O for the amounts) (b) Assume that in 2021 Shamrock, which had been using the UFO method since incorporation in 2018 , changed to the FIFO method of pricing itrventories. Prepare the journal entry necessary to record the change in 2021 and show net income reported for 2018 , 2019,2020 , and 2021 . (Credit occount titles are outomatically indented when amount is entered. Do not indent manuolly if no entry is required, seiect "No Entry" for the occount tities and enter O for the amounts) (b) Assume that in 2021 Shamrock, which had been using the LIFO method since incorporation in 2018 , changed to the FIFO method of pricing imventories. Prepare the journal entry necessary to record the change in 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 occount titles and enter 0 for the amounts.)