The correct answer is C. Microsoft Graph . Microsoft documents that Microsoft 365 Copilot combines large language models with content and context from the Microsoft Graph to generate grounded responses.
Microsoft Graph provides access to organizational data and signals across Microsoft 365 services, including SharePoint , OneDrive , Exchange , Teams , calendars, chats, files, and other work content. When SharePoint data is relevant to the prompt and the user already has permission to access it, Copilot uses Microsoft Graph as the layer that retrieves and grounds that corporate data for the response.
The other options are incorrect for this question. Microsoft Intune is used for endpoint and device management. Microsoft Defender is used for threat protection and security operations. Microsoft Purview provides compliance, governance, data protection, and risk management capabilities. While Copilot honors Purview protections and Microsoft 365 permissions, the specific service it uses to access and ground responses in SharePoint-based corporate data is Microsoft Graph . Therefore, the correct answer is Microsoft Graph .