Which of the following errors would not be detected by a trial balance?

The trial balance is a tool that helps verify the equality of debits and credits in the accounting system. It lists all accounts and their balances, ensuring that the total debits equal the total credits. However, not all errors will necessarily be flagged by this system.

Option C describes a situation where the collection of a receivable is recorded as a debit to Cash and a credit to Accounts Payable. The key aspect of this entry is that it involves incorrect accounts, debiting Cash (which is correct for a collection) but incorrectly crediting Accounts Payable instead of Accounts Receivable. While this error alters the account balances, the total debits and credits remain equal at $300 each. Therefore, the trial balance would not identify this mistake because it does not show discrepancies in the equality of debits and credits.

This is why option C exemplifies an error that would go undetected by a trial balance, making it the correct choice for this question. The other options involve discrepancies that would disrupt the balance of debits and credits, leading to detection in the trial balance.