What must audit committees establish for handling complaints regarding accounting irregularities, according to regulations?

The correct answer focuses on the need for audit committees to have established procedures for receiving and retaining complaints about accounting irregularities. This is essential as it provides a systematic framework for employees, stakeholders, and external parties to report any concerns regarding the financial practices of the organization. These procedures are crucial for ensuring that complaints are documented properly and that appropriate actions can be taken based on the information received.

Having established procedures allows for the effective tracking of complaints and their resolution, fostering an environment where individuals feel safe and encouraged to report wrongdoing. This is an important aspect of corporate governance and compliance, as it helps maintain transparency and accountability within the organization.

In contrast, while a public hotline, a secure mailbox, or internal investigative teams might be beneficial tools, they do not specifically represent the foundational requirement for audit committees as outlined in regulations. The focus is on the procedural aspect, which ensures that organizations have a clear and organized method to handle complaints systematically.