Correct Answer: C
Firestore, part of GCP and of Firebase is the only Database designed for Web and Mobile applications that provides live synchronization and offline support,
Cloud Firestore is a fast, fully managed, serverless, cloud-native NoSQL document database that simplifies storing, syncing, and querying data for mobile, web, and IoT apps at global scale.
Cloud Firestore is the next generation of Cloud Datastore. So Datastore is just the same of Firestore.