On January 1, 2015, Alice Corporation had 20,000 shares of $6 par value common stock and 10,000 shares of 8%, $100 par value convertible preferred stock outstanding. The preferred shares carried a 3 for 1 conversion privilege. As of December 31, 2015, none of the preferred shares had been converted. What number of shares must Alice use in computing diluted earnings per share at December 31, 2015?

a	10,000.
b	20,000.
c	30,000.
d	50,000.