What must auditors verify regarding the information provided during the audit?

Verifying that the information is consistent with the audit period and sample adequacy is crucial for auditors as it ensures that the data being evaluated is relevant and representative of the time frame under scrutiny. This aspect of the audit process confirms that the findings and conclusions drawn from the audit are based on sufficient and appropriate audit evidence. Consistency with the audit period ensures that auditors are assessing the accurate timeframe relevant to the organization's operations, thus ensuring that their analysis reflects the true state of affairs during that specific period. Additionally, ensuring sample adequacy means that the data selected for review provides a comprehensive view of operations, minimizing the risk of oversight and ensuring reliable results in the audit.

The other options, while relevant to the broader context of an audit, do not emphasize the critical aspects of timing and data sufficiency as clearly. Therefore, while policies, the complete history, and external evidence can support the audit findings, the consistency with the audit period and the adequacy of the sample are fundamental to establishing the reliability and validity of the audit conclusions.