Final answer:
Audit standards require the confirmation of accounts receivable, making it mandatory, whereas the confirmation of accounts payable is generally optional and depends on specific audit considerations.
Step-by-step explanation:
When auditing financial statements, the confirmation of accounts receivable and accounts payable can be a significant process. The correct answer to whether confirmation of accounts receivable and accounts payable is required or optional, given that they are significant, is B) Accounts Receivable - Required, Accounts Payable - Optional.
Auditing standards typically require confirmation of accounts receivable because it is a primary way for auditors to verify the existence and accuracy of amounts recorded in the financial statements. However, confirmation of accounts payable is often not required unless there are specific risk factors or concerns about the completeness of the recorded amounts. Nevertheless, auditors might still choose to confirm accounts payable as part of their audit procedures on a case-by-case basis, but it is not a standard requirement.