During 2021, WMC Corporation discovered that its ending inventorles reported on its financial statements were misstated by the following amounts: WMC uses the periodic inventory system and the FIFO cost method. Required: 1. .. Determine the effect of 2019 errors on retained earnings at January 1. 2021, before any adjustments, (lgnore income taxes.) 1-b. Determine the effect of 2020 errors on retained eatnings at January 1.2021 , before any adjustments. (lgnore income taxes) 2. Prepare a joumal entry to correct the error in 2021. 3. Wil WMC account for the error (a) retrospectively or (b) prospectively? Complete this question by entering your answers in the tabs below. Determine the effect of 2019 errors on retained earning5 at January 1, 2021, before any adjustments. (Ignore income taxes.) (If the answers is no effect then select "No effect" In the dropdown.)