A is correct: Copilot connectors ingest external data into Microsoft Graph, enabling declarative agents to use it as grounding knowledge through semantic indexing. The GraphConnectors capability in the agent manifest references specific connection IDs, allowing the agent to reason over indexed external content with citations. Reference: https://learn.microsoft.com/en-us/microsoft-365-copilot/extensibility/overview-copilot-connector
B is incorrect: Declarative agents do not support direct database connections. External data must be made available through Copilot connectors for knowledge grounding or through API plugins for real-time API interactions, not through raw database connection strings. Reference: https://learn.microsoft.com/en-us/microsoft-365-copilot/extensibility/declarative-agent-architecture
C is incorrect: Embedded file content is limited in size, requires manual refresh, and does not scale for ongoing external system integration. Copilot connectors provide automated continuous indexing and semantic search over external data through Microsoft Graph without manual exports. Reference: https://learn.microsoft.com/en-us/microsoft-365-copilot/extensibility/knowledge-sources
D is incorrect: Declarative agents do not support Azure AI Search as a direct knowledge source. Supported knowledge sources include SharePoint, OneDrive, Copilot connectors, email, Teams messages, People, and web search, all configured through the agent manifest capabilities. Reference: https://learn.microsoft.com/en-us/microsoft-365-copilot/extensibility/overview-declarative-agent