Newton Inc. uses a calendar year for financial reporting. The company is authorized to issue 9,000,000 shares of $10 par common stock. At no time has Newton issued any potentially dilutive securities. Listed below is a summary of Newton's common stock activities. 1. Number of common shares issued and outstanding at December 31, 2018 2,000,000 2. Shares issued as a result of a 10% stock dividend on September 30, 2019 200,000 3. Shares issued for cash on March 31, 2020 2,000,000 Number of common shares issued and outstanding at December 31, 2020 4,200,000 4. A 2-for-1 stock split of Newton's common stock took place on March 31, 2021 Instructions a. Compute the weighted-average number of common shares used in computing earnings per common share for 2019 on the 2020 comparative income statement. b. Compute the weighted-average number of common shares used in computing earnings per common share for 2020 on the 2020 comparative income statement. c. Compute the weighted-average number of common shares to be used in computing earnings per common share for 2020 on the 2021 comparative income statement. d. Compute the weighted-average number of common shares to be used in computing earnings per common share for 2021 on the 2021 comparative income statement.