Comprehensive and Detailed In-Depth Explanation:

A combined audit is when multiple management systems (e.g., ISO 9001 for Quality, ISO 14001 for Environmental Management, and ISO 45001 for Occupational Health & Safety) are audited together in a single organization.

Clause References:

ISO 19011:2018, Clause 5.4 – Combined Audits:

A combined audit is performed when two or more management systems are assessed simultaneously at the same auditee.

Why is the Correct Answer A?

A combined audit reduces duplication of effort by auditing multiple standards together at a single organization.

Example: A company certified to both ISO 9001 and ISO 14001 can have one audit covering both standards.

Why are the Other Options Incorrect?

B (Two or more auditing organizations cooperating on a single auditee) → This is a joint audit, not a combined audit.

C (Two or more management systems audited at multiple auditees) → This is a multiple-site audit, not a combined audit.