You are creating a prompt in Microsoft 365 Copilot to get information about a proposal.

According to Microsoft AI Business Professional guidance for Microsoft 365 Copilot, grounding a response means ensuring the AI generates output based on specific, authoritative content rather than relying on generalized training data. When working with enterprise documents such as proposals, grounding is achieved by explicitly referencing the source material within the prompt.

Option C is correct because referencing the proposal content directs Copilot to use that specific document as the primary context for generating the response. Microsoft documentation emphasizes that effective prompts should include clear context and explicit references to relevant files, meetings, emails, or documents stored in Microsoft 365. This reduces hallucinations and ensures factual alignment with organizational data.

Option A is incorrect because relying on training data increases the risk of inaccurate or fabricated information. Options B and D improve prompt clarity but do not guarantee grounding in the proposal itself.

Therefore, explicitly referencing the proposal content is the most reliable and best practice method for ensuring grounded, accurate responses in Microsoft 365 Copilot.