errors

a payables ledger control account showed a credit balance if $768 420. The payables ledger balances totalled $781 200.

Which one of the following possible errors could account in full for the difference?

A. a contra against a receivables ledger debit balance of 6390 has been entered on the credit side of the payables ledger control account.
( a contra is supposed to be debited to the payables c/a hence… not sure )
B. the total of discount allowed 28400 was entered to the debit side of the payables ledger control account instead of the correct figure for discount received of 15 620 .
( i dont undertsand al l these debit and credit terms)
C. 12780 cash paid to a supplier was entered on the credit side of the supplier account in the payables ledger.
D. total of discount received 6390 has been entered on the credit side of the payables ledger control account.

Mr moffat can you break down the quetsion and simplify it? Thank you