Which of the following statements best captures the relationship among the three sets of audit standards developed by the AICPA's Auditing Standards Board (ASB), by the Public Company Accounting Oversight Board (PCAOB) and by the International Auditing and Assurance Standards Board (IAASB)?

a. Audit standards developed by the ASB are the oldest and those developed by the IAASB are the most recently developed, with those developed by the PCAOB falling in the middle of the timeline.

b. Audit standards developed by the ASB apply to US companies whereas those developed by the PCAOB and IAASB pertain to non-US companies.

c. The ASB and IAASB work closely together but the audit standards developed by the PCAOB are the gold standard.

d. The ASB and PCAOB standards are largely converged while the IAASB audit standards feature several idiosyncratic requirements (related to, e.g., information security under international law).

e. The ASB audit standards apply to audits of US private entities, the PCAOB audit standards apply to audits of US public companies (i.e., those registered with the SEC), and the IAASB audit standards apply to audits of non US companies in over 125 jurisdictions.