Comprehensive and Detailed In-Depth Explanation:

A technical expert is someone with specialized knowledge that helps the audit team understand specific technical aspects of the auditee’s processes.

Clause References:

ISO 19011:2018, Clause 7.3.4 – Use of Technical Experts:

Technical experts support the audit team with specialized knowledge but do not perform the audit themselves.

Why is the Correct Answer B?

A technical expert is needed when auditors lack deep expertise in specific areas, such as engineering, software, or medical devices.

They assist in interpreting complex technical requirements but do not act as auditors.

Why are the Other Options Incorrect?

A (Observer) → Observers do not contribute expertise; they only watch the audit (e.g., trainees).

C (Guide) → Guides help with logistics but do not provide technical expertise.