If former employees potentially still have access to services through consumer Google accounts, what should you do?

The option of using the Transfer Tool for Unmanaged Accounts is effective because it allows organizations to reclaim access to data and resources that may still be linked to former employees' consumer Google accounts. By transferring these unmanaged accounts to the organization as managed accounts, the organization can exert control over them, enforce security policies, and ensure that no sensitive information is left vulnerable or accessible by former employees.

This approach effectively mitigates risks associated with former employees retaining access to company data. It allows for a proactive stance toward security by centralizing management of these accounts under the organization's domain. Once the accounts are transferred, the organization can apply appropriate access controls, monitor usage, and enforce any required security measures tailored for their environment.

The other options, while they may seem relevant, do not provide a direct solution to reclaiming access or securing the data associated with the former employees' accounts efficiently.