Comprehensive and Detailed Step-by-Step Explanation:
* Reference to IIA Standards:
* Standard 1210 - Proficiency: Internal auditors must possess the necessary knowledge, skills, and competencies to conduct audits effectively.
* The auditor should have the relevant expertise to evaluate investment-related test attributes.
* Reasoning:
* Option Ais correct because the auditor has direct knowledge and expertise in investments, making them the most qualified to determine the relevant test attributes for the audit.
* Option B(IT audit experience) does not align with the specific skills required for investment auditing.
* Option C(previous experience) may offer some advantage, but the lack of familiarity with the current organization's processes limits the auditor's effectiveness.
* Importance of Expertise:
* Selecting an auditor with relevant experience and proficiency ensures that the audit will be conducted with accuracy and that the proper test attributes will be identified.