Armstrong Inc. is a calendar-year corporation. Its financial statements for the years ended 12/31/17 and 12/31/18 contained the following errors: 2017 2018 Ending inventory $50,000 understatement $20,000 overstatement $80,000 understatement $40,000 overstatement Depreciation expense Assume that the 2017 errors were not corrected and that no errors occurred in 2016. By what amount will 2018 income before income taxes be overstated or understated? Select one: O O O O a. $30,000 overstatement b. $30,000 understatement c. $70,000 understatement d. $70,000 overstatement