To securely share data using Google Vault for an investigation:
* Suspend the user's account to prevent further changes to their data.
* Use Google Vault to search for all associated user data relevant to the investigation.
* Export the data securely from Google Vault. These steps ensure that the data remains intact and secure throughout the investigation process.
References:
* Google Workspace Admin Help - Export data from Google Vault
* Google Workspace Admin Help - Manage user accounts

"Depending on what you're migrating, you need to turn on the relevant service (Gmail for email, Directory for contacts, and Google Calendar for calendar events)."
- https://support.google.com/a/answer/9158145?hl=en

To set permissions and ensure that the recruiting firm employees can't remove the files, follow these steps:
* Sign in to the Google Admin console: Use an account with super administrator privileges.
* Create a Shared Drive:
* Go to Drive and Docs > Manage shared drives.
* Click on "Create a shared drive" and give it a name relevant to the recruiting project.
* Add members and set permissions:
* Click on the shared drive.
* Add the HR team and the recruiting firm employees as members.
* Grant "Contributor" access to the HR team, which allows them to edit and collaborate on documents but not delete them.
* Grant "Viewer" or "Commenter" access to the recruiting firm employees if they only need to review the documents without editing.
References:
* Google Workspace Admin Help - Shared Drives
* Google Workspace Admin Help - Permissions for shared drives

A is not correct because Inbound Gateways are to help with managing spam, not mail storage.
B is correct because comprehensive mail storage will store the messages in associated mailboxes.
C is not correct because this is not a best practice.
D is not correct because this does not change anything with regard to spam filtering.
Reference:
https://support.google.com/a/answer/2956491?hl=en