The best actions are F and A .
F). Urgently contact the certification body and explain the situation - Correct This is the first and most important action. In a third-party certification audit, the certification body controls the audit programme, audit team appointment, audit duration, audit competence, and certification process. If a team member leaves unexpectedly, especially where that person is also evaluating a first-time audit team leader, the certification body must be informed immediately so it can decide how the audit should proceed.
A). Ask the auditee if they could accept to extend the audit till the following day - Correct Because the second auditor could return the next day, extending the audit is a practical solution, provided the certification body agrees. This helps ensure the planned audit activities, required audit time, audit team competence, and evaluation of the audit team leader can still be completed properly.
The other options are not the best responses:
B is too extreme. The audit does not need to be cancelled immediately if it can be completed by adjusting the plan with certification body approval.
C is not appropriate without certification body approval, because continuing alone may reduce planned audit coverage and affect audit team competence or required audit duration.
D is not sufficient because the auditee cannot decide whether the certification audit can continue with a changed audit team.
E is less suitable than F because you should first explain the full situation to the certification body. The certification body may then decide whether a replacement audit team leader is needed, whether the audit should be extended, or whether another action is required.
Therefore, the correct selected options are A and F .

According to ISO/IEC 17021-1:2015 Clause 9.4.5 and 9.5.1:
Certification decisions are based on:
The audit conclusions,
Acceptance of corrective action plans for minor nonconformities (A),
Acceptance of corrections for major nonconformities (C),
Confirmation that the scope is fulfilled (B).
Full legal compliance (D) is not a requirement for certification decisions rather, it is the effectiveness of the management system to meet compliance obligations that is assessed.
Reference: ISO/IEC 17021-1:2015 Clause 9.4.5 and 9.5.1; ISO 14001:2015 Clause 9.1.2.

The correct answers are D and F .
A second-party audit is an external audit carried out by an organization that has an interest in the auditee, such as a customer auditing a supplier , or by another party acting on that customer's behalf.
Therefore:
C). An auditor from a customer - participates
This is the clearest example of a second-party audit.
A). An auditor employed by an external consultancy organisation - may participate A consultancy auditor may conduct the audit on behalf of the customer or interested party, so this can still be a second-party audit.
B). An auditor certified by an auditor certification body - may participate Auditor certification is a competence credential. It does not determine whether the audit is first-party, second- party, or third-party.
E). An auditor trained in the CQI and IRCA scheme - may participate
Training or qualification does not define the audit type. Such an auditor may participate in a second-party audit if acting for the customer or interested party.
D). A certification body auditor - does not participate in a second-party audit A certification body auditor performs third-party audits , such as ISO 14001 certification audits.
F). An auditor from an accreditation body - does not participate in a second-party audit An accreditation body auditor assesses certification bodies, not suppliers or organizations as part of a customer-related second-party audit.
So, the two roles that do not participate in a second-party ISO 14001 audit are D. Certification body auditor and F. Auditor from an accreditation body .

The correct answers are A and B.
The nonconformity concerns ABC's failure to communicate relevant environmental requirements to an external provider. This relates mainly to ISO 14001:2015 Clause 8.1 - Operational planning and control, which requires the organisation to ensure that outsourced processes are controlled or influenced and that relevant environmental requirements are communicated to external providers.
A). We revised the contract to add the relevant environmental requirements - Correct This is the immediate correction. The specific contract that caused the nonconformity has been amended so that the maintenance provider receives the relevant environmental requirements.
B). We revised the procurement process - Correct
This is the stronger systemic corrective action. Revising the procurement process helps prevent recurrence by ensuring future contracts or purchasing arrangements include relevant environmental requirements before external providers are approved or work begins.
The other options are less suitable:
C may be useful background work, but it does not directly correct the failure to communicate requirements.
D is only a future discussion, not a completed corrective action.
E may help verify effectiveness later, but it is not the corrective action itself.
F may support implementation, but training alone is weaker than changing the process that allowed the omission.
Therefore, the best corrective actions are A and B.