To ensure that Google Calendar suggests nearby office rooms when a user creates an event, you need to associate both the users and the room resources with their respective locations within the Google Workspace organizational structure. The most effective way to do this is by organizing users into organizational units (OUs) based on their location and then associating the room resources with the corresponding OUs.

The core of the problem is to identify the responsible users and the extent of past unauthorized sharing. The Security Investigation Tool is designed precisely for this purpose. It allows administrators to search and analyze various audit logs, including Drive logs, to pinpoint specific events, users, and data.
Here's why the other options are less appropriate as the first or most direct action for this specific problem:
A . Review the organization's sharing policies in the Admin console, and update the policies to prevent external sharing. This is a crucial preventative measure for the future, and a necessary step after identifying the scope of the problem. However, it won't help you identify who shared what in the past.
B . Use the security health page to identify misconfigured sharing settings in Drive. The security health page provides an overview of your security posture and can highlight general misconfigurations. While useful for identifying potential vulnerabilities, it won't give you the granular details of specific users and shared documents that have already occurred, which is what the question asks for.
D . Create an activity rule in the Security Center to alert you of future external sharing events. Similar to option A, this is a future-oriented preventative and monitoring measure. It will help catch future violations but won't provide information about the past unauthorized sharing that has already happened.
Reference from Google Workspace Administrator:
Security investigation tool: This tool is explicitly designed for identifying, triaging, and taking action on security issues. It allows administrators to search and analyze logs from various Google Workspace services, including Drive, to investigate specific events like external sharing.
Reference:
Drive audit log events: The security investigation tool leverages audit logs. Drive audit logs capture events such as document sharing, changes in sharing permissions, and access.

When multiple users across different office buildings experience issues with a Google Workspace service like Google Voice (dropped calls, poor call quality), the first and most efficient step to determine if it's a widespread service disruption or a localized issue is to check the official Google Workspace Status Dashboard. This dashboard provides real-time and historical information on the status of all Google Workspace services.

The key information here is "only five users" and "Agency users must have their original email address. You have added the agency's domain as a secondary domain." For a small number of users (five), manually creating them in the Admin console is the most straightforward and least complex method. When creating a new user, the Admin console allows you to select the domain for their primary email address from any secondary domains you have added to your Google Workspace account.

Switching the former employee's account to an Archived User license ensures that their data and documents are preserved, and access is retained for the manager and team without incurring the full cost of an active Workspace license. Archived User licenses are a cost-effective way to maintain access to documents while preventing unauthorized access to the account.