Demonstrating due professional care involves assessing the cost of assurance in relation to the potential benefits (Option D).
This approach ensures that internal audit resources are used efficiently and effectively, providing value to the organization.
According to IIA Standards, Standard 1220: Due Professional Care, internal auditors must consider the extent of work needed to achieve the engagement's objectives and the relative complexity, materiality, or significance of matters to which assurance procedures are applied. Staffing audit engagements with qualified auditors (Option A), relying on prior work (Option B), and guaranteeing identification of all significant risks (Option C) do not fully encapsulate the essence of due professional care, which balances cost and benefit.
References:
* IIA Standards, Standard 1220: Due Professional Care
* IIA's International Professional Practices Framework (IPPF)