ZAG has the following liabilities: accounts payable $10,000; deferred taxes $50,000; sinking fund, long-term debt of $40,000 with four equal annual payments of $10,000 remaining on its term; convertible long-term debt of $10,000 which is convertible immediately; and a demand loan to the bank for $20,000. What is the amount of ZAG's current liabilities?a)$40,000. b)$50,000. c)$60,000. d)$70,000.