A deb it balance on a suppliers' account has been wrongly included in the closing list of debtors' balances. The effect of this error is:

(a) an overstatement of the list of debtors in relation to the correct amount shown on the debtors' control account;

(b) an understatement of the list of creditors in relation to the correct amount shown in the creditors' control account;

(c) both

(a) and

(b) above;

(d) none of the above.