Swifty Corporation had 1500000 shares of common stock issued and outstanding at December 31, 2017. On July 1, 2018 an additional 1250000 shares were issued for cash. Swifty also had stock options outstanding at the beginning and end of 2018 which allow the holders to purchase 371000 shares of common stock at $20 per share. The average market price of Swifty's common stock was $25 during 2018. What is the number of shares that should be used in computing diluted earnings per share for the year ended December 31, 2018?

2199200

2217950

2824200

2421800