正解:A
Independence would be most impacted if an IS auditor were to assist with the implementation of recommended control enhancements, as this would create a conflict of interest and impair the objectivity and credibility of the IS auditor. Integrity, materiality, and accountability are important attributes of an IS auditor, but they are not directly affected by the involvement in the implementation of control enhancements. References: CISA Review Manual (Digital Version), Chapter 1: Information Systems Auditing Process, Section 1.1: IS Audit Standards, Guidelines and Codes of Ethics