Give the following information,what is the balance on the trade payables control access December?
Credit balance on the creditors control account as at 1 January    4600
Trasactions for the year 1 Jan to 30 Dec   
Discount received                                   1000
Credit purchases                                     54000
Credit purchase returns                           6000
Refunds received from suppliers              2000
PAyments to suppliers                              39000
Balance in credit ledger set off against debtors ledger          1000
A.8600
B.9600
C.12600
D.13600
最好能详细点，谢谢！！！