An organization needs a flexible and scalable NoSQL database with strong web and mobile application support. Which Google Cloud product or service should the organization use?

Cloud Spanner is a globally distributed relational database with strong consistency and SQL support, making it a relational (NewSQL) solution rather than a NoSQL database.

Cloud Storage is an object storage service for unstructured data like files and blobs, not a database for application data queries.

BigQuery is a serverless data warehouse optimized for large-scale analytical queries, not for transactional web or mobile application workloads.

Firestore is a fully managed, serverless NoSQL document database that offers a flexible schema, horizontal scaling, and official client SDKs for web, iOS, and Android. It supports real-time data synchronization and offline support, making it purpose-built for web and mobile applications. Its document-collection data model accommodates varied and evolving data structures without schema migrations.