Correct Answer - B.
You can select either existing Kinesis Stream or create a new Kinesis Stream to have Amazon Cognito Streams push all sync data to these streams.
Apart from this, an IAM role is required to grant Amazon Cognito to put data events to these streams.
Option A is incorrect as Both the existing Kinesis Stream or a new Kinesis Stream can be used.
Option C is incorrect as the IAM role is needed here instead of an IAM user.
Option D is incorrect as IAM roles should be selected which grants Amazon Cognito permission to publish to this Stream.