Martinez 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. Net Income Retained Earnings (Ending Balance) Under FIFO Under Average-Cost Under FIFO 2015 $95,100 $85,600 $101,700 2016 65,400 60,500 144,400 2017 98,200 89,000 223,500 2018 116,400 125,600 342,200 2019 279,800 269,000 551,600 2020 334,700 339,800 781,600 (a) What is the beginning retained earnings balance at January 1, 2017, if Martinez prepares comparative financial statements starting in 2017? Retained earnings, January 1 $ (b) What is the beginning retained earnings balance at January 1, 2020, if Martinez prepares comparative financial statements starting in 2020? Retained earnings, January 1 $ (c) What is the beginning retained earnings balance at January 1, 2021, if Martinez prepares single-period financial statements for 2021? Retained earnings, January 1 $ (d) What is the net income reported by Martinez in the 2020 income statement if it prepares comparative financial statements starting with 2018? Net Income $ 2018 2019 $ 2020