AWS Certified Developer Associate (#132)

A Developer is building a mobile application and needs any update to user profile data to be pushed to all devices accessing the specific identity. The Developer does not want to manage a back end to maintain the user profile data. What is the MOST efficient way for the Developer to achieve these requirements using Amazon Cognito?

Use Cognito federated identities.
Use a Cognito user pool.
Use Cognito Sync.
Use Cognito events.