Final answer:
The American Institute of Certified Public Accountants (AICPA) is the authoritative body designated to promulgate attestation standards.
Step-by-step explanation:
The authoritative body designated to promulgate attestation standards is the American Institute of Certified Public Accountants (AICPA).
The AICPA establishes and updates the Generally Accepted Auditing Standards (GAAS) which are used by auditors to conduct audits and attestation engagements. These standards provide the framework for auditors to follow when attesting to the fairness and accuracy of financial statements or other information.
The AICPA's Auditing Standards Board (ASB) is responsible for issuing and maintaining the attestation standards, which include the Statements on Standards for Attestation Engagements (SSAE) for engagements such as reviews and examinations.