Comprehensive and Detailed Step-by-Step Explanation:

Reference to IIA Standards:

Standard 2210 - Engagement Objectives: Audit objectives must align with the engagement scope and focus on evaluating compliance, efficiency, and effectiveness.

Reasoning:

Option C is correct because assessing compliance with HR policies is a specific, measurable, and relevant objective aligned with internal audit’s role in evaluating governance and control processes.

Option A (analyzing turnover rates) is more investigative and does not align with assessing processes or compliance.

Option B (evaluating common practices) is vague and lacks a clear link to controls, policies, or risks.

Impact of Clear Objectives:

Well-defined objectives, like compliance assessment, ensure the audit delivers actionable insights and adds value to the organization.