Final answer:
Supporting schedules are audit documentation that must consist of either reconciliation of amounts or substantive analytical procedures, and are used by auditors during the audit process. (Option C).
Step-by-step explanation:
The correct answer to the student's question about supporting schedules is C) must consist of either reconciliation of amounts or substantive analytical procedures.
Supporting schedules are part of the audit documentation that provides details and support for the accounts in the financial statements. They are used by auditors to gain a better understanding of the financial information and to verify the accuracy and completeness of the reported amounts.
Supporting schedules do not necessarily make up the largest portion of audit documentation, nor are they required to be prepared by the auditor, as they can be prepared by the client's management as well. However, auditors are responsible for reviewing and testing these schedules as part of the audit process.