At December 31, 2022, St. Johns Limited had 4,000,000 common shares outstanding (no preferred shares issued). An additional 250,000 common shares were issued on July 1, 2023, and 500,000 more on October 1, 2023. As well, on April 1, 2023, St. Johns issued 10,000, $1,000 face value, 8% convertible bonds. Each bond is convertible into 40 common shares. No bonds were converted in 2023. What is the number of shares to be used in calculating basic earnings per share and diluted earnings per share, respectively, for 2023?

a. 4,250,000 and 4,550,000

b. 4,250,000 and 4,250,000

c. 4,250,000 and 4,650,000

d. 4,750,000 and 5,050,000