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?

A. Use Cognito federated identities.
B. Use a Cognito user pool.
C. Use Cognito Sync.
D. Use Cognito events.