Accounting · Suspense Account

Which of the following accounting errors would cause an imbalance in the trial balance, thereby requiring a suspense account entry? (i) A machine's cost was recorded in appropriate ledger accounts as $4,280 instead of the correct $8,240. (ii) Discounts received were credited to the discounts received account and debited to the suspense account. (iii) Total purchases for March were debited to trade payables and credited to purchases. (iv) A contra entry was debited to the payables account and credited to the receivables account.