How should you manage these consumer user accounts with Cloud Identity?

You are onboarding new users into Cloud Identity and discover that some users have created consumer user accounts using the corporate domain name.

How should you manage these consumer user accounts with Cloud Identity?
A . Use Google Cloud Directory Sync to convert the unmanaged user accounts.
B . Create a new managed user account for each consumer user account.
C . Use the transfer tool for unmanaged user accounts.
D . Configure single sign-on using a customer’s third-party provider.

Answer: C

Explanation:

https://support.google.com/a/answer/6178640?hl=en

The transfer tool enables you to see what unmanaged users exist, and then invite those unmanaged users to the domain.