If a Trial Balance balances when the Trade receivables control account balance is included in it and does not when the sum of the list of customers’ account balances is included, it would be obvious that the error is in:

(a) The individual customers’ accounts in the Trade receivables ledger

(b) The Trade receivables control account

(c) Either the Receivables control account or the individual accounts of the Receivables ledger

(d) Neither the Receivables control account nor the individual customers’ accounts