By performing an audit engagement, the internal audit activity can systematically review and assess the current risk management practices in the electricity sales processes. This will provide senior management with a detailed understanding of the existing controls, processes, and any gaps or areas for improvement. An audit engagement offers a structured approach to identifying and evaluating risks and controls, which is essential for developing effective risk management strategies. References: The IIA's International Standards for the Professional Practice of Internal Auditing (Standards), specifically Standard 2200 - Engagement Planning, and Standard 2210 - Engagement Objectives.

The scenario that best illustrates the concept of due professional care is when an internal auditor establishes engagement objectives, reviews processes systematically, and assures process owners that all significant risk events were identified and tested using a disciplined approach. This scenario reflects adherence to the standard of due professional care which mandates that internal auditors must apply the care and skill expected of a reasonably prudent and competent auditor.
The IIA's International Standards for the Professional Practice of Internal Auditing, particularly those standards related to due professional care.

The scenario describes the internal audit team providing both assurance and consulting services. Initially, the internal audit team was engaged in an assurance activity, verifying the effectiveness of controls through standard audit procedures. However, upon discovering a knowledge gap among employees, the team extended their role to include consulting services by conducting training sessions. This mix of both assurance and consulting in the same engagement characterizes what are commonly referred to as blended services.
Institute of Internal Auditors (IIA) - International Standards for the Professional Practice of Internal Auditing

An example of a detective control is confirmation with suppliers and vendors. This control involves verifying transactions after they occur to ensure accuracy and authenticity, helping to detect errors or fraud in the organization's operations with external parties.
Internal control concepts and definitions from authoritative sources like the Committee of Sponsoring Organizations of the Treadway Commission (COSO).

The internal audit charter should include the Definition of Internal Auditing, along with the Core Principles, Code of Ethics, and Standards. This definition provides clarity on the purpose, authority, and responsibility of the internal audit function within the organization. References:
* IIA's International Professional Practices Framework (IPPF) - Internal Audit Charter requirements.