Your organization offers public mobile apps and websites. You want to migrate to a Google Cloud-based solution for checking and maintaining your users' username...

Your organization offers public mobile apps and websites. You want to migrate to a Google Cloud-based solution for checking and maintaining your users' usernames and passwords and controlling their access to different resources based on their identity.
Which should your organization choose?

A. VPN tunnels B. Identity Platform C. Compute Engine firewall rules D. Private Google Access