Why were the internal auditors of Bank All Ltd. unavailable for the AML audit?

The internal auditors of Bank All Ltd. were unavailable for the AML audit because they were reviewing another bank's compliance regime. This situation suggests that their expertise was being utilized to evaluate and enhance the compliance efforts of another institution, which can often happen in the auditing field as auditors may share insights and best practices between organizations. Engaging in such tasks reflects a commitment to maintaining high compliance standards and leveraging shared knowledge within the industry, which can be crucial for understanding various compliance frameworks and improving practices at their own institution.

The other options present scenarios that could lead to internal auditors' unavailability, but reviewing another bank's compliance regime specifically indicates a direct engagement that involves their professional auditing skills, making it more relevant to their primary responsibilities and expertise in auditing and compliance. The training and seminars mentioned in other options are valuable but would not typically involve the auditors' direct engagement with compliance audits for their own organization. Additionally, being on leave is a more passive reason and does not imply a professional engagement that contributes to the auditors' skill set or the organization’s compliance culture in the same proactive way.