You are building an application that stores relational data from users. Users across the globe will use this application. Your CTO is concerned about the scalin...

You are building an application that stores relational data from users. Users across the globe will use this application. Your CTO is concerned about the scaling requirements because the size of the user base is unknown. You need to implement a database solution that can scale with your user growth with minimum configuration changes.
Which storage solution should you use?

A. Cloud SQL B. Cloud Spanner C. Cloud Firestore D. Cloud Datastore