Comprehensive and Detailed in Depth Explanation:

Huawei's experience assurance solutions focus on enhancing user and application performance within network environments. The HCSA-Sales-IP Network V6.0 documentation highlights the following:

VIP experience assurance (A): This ensures prioritized network performance for critical users (e.g., executives or key clients) through QoS (Quality of Service) policies and traffic management, a key feature of Huawei's intelligent network solutions.

Energy saving (B): While Huawei incorporates energy-saving technologies (e.g., in switches and routers), it is not categorized as an ''experience assurance solution.'' It falls under sustainability features rather than direct user/application experience enhancement.

Application experience assurance (C): This involves optimizing application performance through technologies like application-based traffic steering and latency reduction, a core component of Huawei's network management offerings.

Visualized O&M (D): Operations and Maintenance (O&M) visualization provides real-time network monitoring and analytics, ensuring a proactive approach to maintaining user experience, as supported by tools like iMaster NCE-Campus.

Thus, A, C, and D are the correct answers as per Huawei's focus on experience assurance.