Assertions play a key role in the external audit of any firm. Assertions represent an efficient and systematic method of auditing a client's accounts and disclosures. At what point in the audit are assertions most likely to be used by the auditor? O Assertions are typically utilized by the auditor during the final stages of the audit, when the auditor is checking assertions related to presentation and disclosure. O Assertions may be used by the auditor at various stages during the audit, and may relate to risk assessment procedures and helping the auditor determine appropriate types of evidence to collect. Assertions are typically used by the auditor during the preliminary phases of the audit, as they only relate to risk assessment procedures conducted by the auditor. O Assertions are usually determined during the preliminary stages of the audit, with the internal audit function typically assuming responsibility for assertions relating to areas of higher risk.