Three secure options for storing the contents of the Operator CD while still allowing access upon a planned Vault restart include: 1. Storing the CD in a physical safe and mounting it every time Vault maintenance is performed ensures physical security and controlled access. 2. Copying the entire contents of the CD to the system Safe on the Vault integrates the data with the Vault's existing security infrastructure, ensuring both accessibility and protection. 3. Storing the server key in a Hardware Security Module (HSM) and copying the rest of the keys from the CD to a folder on the Vault Server and securing it with NTFS permissions leverages hardware-level security and access control on the server level. Option C, which involves copying the contents to a folder secured with only NTFS permissions, solely relies on file system security, which is less robust compared to the other options.