You use Microsoft 365 Copilot.

Microsoft 365 Copilot provides structured ways to persist and reuse knowledge sources to avoid repeatedly uploading the same files.

Creating a notebook that references the five files (Option B) allows those documents to remain attached within a persistent workspace. Copilot can then consistently ground responses in those files without re-uploading them for every conversation.

Creating an agent with a defined knowledge source (Option D) also provides a reusable solution. By configuring the five files as part of the agent’s knowledge base, the agent can automatically reference them in future interactions.

Saving a prompt does not persist file attachments. Fine-tuning models is not part of standard Microsoft 365 Copilot user workflows. Uploading a ZIP file does not improve reference management and may reduce accessibility of individual documents.

Therefore, the correct solutions are to create a notebook that references the files and to create an agent with a knowledge source.