classic artists' services signed a contract with a maintenance service company to maintain a building that classic will use for office purposes. the contract states that the work will begin work on february 1 and end on may 31. classic artists' will pay the maintenance service company $16,000 at the end of may. it accrues maintenance expense at the end of every month. what is the balance in the accounts payable account for amounts owed to the maintenance service company at the end of marc