The audit plan of an internal audit function includes an assurance engagement of the organization’s...

Comprehensive and Detailed Explanation:

Per IIA Standard 1210 – Proficiency, engagements must be performed by auditors with the necessary skills. If resources are not available, the engagement supervisor cannot unilaterally suspend or reassign staff without CAE input. The appropriate action is to escalate the issue to the CAE (D), who has authority to adjust the audit plan, bring in external expertise, or reallocate resources. Option A may not be feasible due to scheduling conflicts. Options B and C prematurely halt the engagement, which undermines assurance delivery. The CAE is responsible for ensuring resource adequacy (per Standard 2030 – Resource Management). Therefore, the engagement supervisor must seek guidance from the CAE.