A is incorrect: A system Fallback topic is triggered when the agent cannot find an answer or encounters an error. It doesn't actively control the length or source of generative answers; it merely provides a backup response mechanism.
B is incorrect: Enabling 'Require user authentication' secures access to the SharePoint knowledge source, ensuring only authorized users can receive information. However, it does not influence the AI's tendency to include external web content or the verbosity of its responses.
C is correct: The 'Custom instructions' (system prompt) field in the Generative Answers node allows you to provide specific directives to the AI model, such as instructing it to keep answers concise, within a certain length, or in a particular format, directly addressing the verbosity issue.
D is correct: Setting the 'Content moderation' strictness level to 'High' compels the Copilot agent to rely exclusively on its configured knowledge sources, significantly reducing the likelihood of it pulling in external web information or 'hallucinating' responses.