Pronghorn Company started operations on January 1, 2015, and has used the FIFO method of inventory valuation since its inception. In 2021, it decides to switch to the average-cost method. You are provided with the following information. 2015 2016 2017 2018 2019 2020 Net Income Under FIFO Under Average-Cost $108,100 $97,500 64,700 60,000 89,200 80,000 125,700 136,100 323,100 312,200 310,200 315,500 Retained Earnings (Ending Balance) Under FIFO $91,300 157,900 239,300 332,400 648,700 843,200 (a) What is the beginning retained earnings balance at January 1, 2017, if Pronghorn prepares comparative financial statements starting in 2017? Retained earnings, January 1 (b) What is the beginning retained earnings balance at January 1, 2020, if Pronghorn prepares comparative financial statements starting in 2020? Retained earnings, January 1 (c) What is the beginning retained earnings balance at January 1, 2021, if Pronghorn prepares single-period financial statements for 2021? Retained earnings, January 1 (d) What is the net income reported Pronghorn in the 2020 income statement if it prepares comparative financial statements starting with 2018? 2018 2019 2020 Net Income