If, after the audit release date, auditors determine that an important auditing procedure was omitted, which of the following initial courses of action is most appropriate? A) Perform the omitted procedure or an alternative procedure. B) Notify the board of directors and regulatory agencies that are currently relying on auditors' reports. C) Determine whether the omitted procedure is important in supporting the auditors' opinion on the entity's financial statements. D) Engage another public accounting firm to conduct a quality assurance review