Budgeted sales of shirts were 50,000 for December. It takes 4 buttons to make one shirt. Actual and budgeted inventories are as follows: Actual inventories at 12/1: shirts, 10,000; buttons, 40,000. Budgeted inventories at 12/31: shirts, 15,000; buttons, 60,000. How many buttons must be purchased in December?

A. 200,000

B. 220,000

C. 225,000

D. 240,000

E. 245,000