On December 31 of the current year, the assets and liabilities of Tree, Inc. are as follows: Cash $30,000; Supplies, $600; Equipment, $10,000; Accounts Payable, $8,500. What is the amount of equity as of December 31 of the current year? a $12,100. b $30,900 c $10,900 d $32,100 e $49,100