Explanation
This answer states that eliciting requirements, documenting requirements, analyzing information, and facilitating solutions are the key activities that the BA must complete prior to beginning development for a Service Cloud implementation at UC. Eliciting requirements means that the BA gathers and clarifies the needs, expectations, and objectives of the stakeholders for the Service Cloud implementation. Documenting requirements means that the BA records and organizes the information obtained from eliciting requirements in a clear and concise way. Analyzing information means that the BA reviews and evaluates the information obtained from documenting requirements to identify gaps, issues, or opportunities for improvement.
Facilitating solutions means that the BA proposes and validates possible solutions or alternatives for addressing the gaps, issues, or opportunities for improvement identified from analyzing information. Eliciting requirements, documenting requirements, analyzing information, and facilitating solutions are the key activities that the BA must complete prior to beginning development for a Service Cloud implementation because they help the BA to define and communicate the scope and specifications of the Service Cloud implementation, and to ensure that they meet the stakeholder's needs, expectations, and objectives.
References:https://trailhead.salesforce.com/en/content/learn/modules/salesforce-business-analyst-quick-look/use

Explanation
The business analyst should use the metadata coverage report to determine which changes must be made manually in each environment. The metadata coverage report is a tool that shows which metadata types and components are supported in different development models and tools, such as change sets, Metadata API, Salesforce CLI, etc. The business analyst should use the metadata coverage report to identify which changes can be deployed automatically using declarative change sets and which changes must be made manually using other tools or methods. The object schema builder is not a resource to determine which changes must be made manually in each environment. The object schema builder is a tool that lets you create and modify custom objects and fields using a graphical interface. It does not show which metadata types and components are supported in different development models and tools. The setup audit trail is not a resource to determine which changes must be made manually in each environment. The setup audit trail is a tool that tracks the recent setup changes that you and other admins have made to your org. It does not show which metadata types and components are supported in different development models and tools.
References:https://trailhead.salesforce.com/en/content/learn/modules/application-lifecycle-and-development-mod