The assets of Jason's business increased by $60 000 and the liabilities increased by $20 000 during the current year. If the profit for this period was $48 000, what additional contribution or withdrawal was made by the owner? (Assume only a withdrawal or a contribution was made.)

a. Contribution $8 000

b. Contribution $12 000

c. Drawings $8 000

d. Drawings $12 000