On 1/1/2020, a company had 1,200 common shares outstanding. On March 1, 2020, the company sold 300 shares of common treasury stock acquired in 2019. On December 1, 2020, the company acquired 180 shares of its own outstanding common stock. Weighted-average common shares outstanding for 2020 is

a. 478

b. 1,200

c. 1,000

d. 1,435

e. 1,320