Comprehensive and Detailed Step-by-Step Explanation:

Reference to IIA Standards:

Standard 2200 - Engagement Planning: The engagement work program outlines the resources, timelines, and procedures necessary to achieve the engagement’s objectives.

The work program must be approved to ensure alignment with objectives and resource requirements.

Reasoning:

Option B is correct because an approved engagement work program confirms that the scope, procedures, and resources were planned and allocated effectively.

Option A (staff skills audit) evaluates team competencies but does not confirm specific resource allocation for an engagement.

Option C (post-engagement survey) evaluates the outcome of the audit but does not provide evidence of initial resource planning.

Significance of the Work Program:

The work program ensures that the engagement is structured to meet objectives efficiently, with adequate and relevant resources.