Which of the following is the correct way to load streaming data into Amazon OpenSearch Service from different sources?

Answer options:

A.Load streaming data from Amazon Kinesis Data Firehose using AWS Lambda functions as event handlers.
B.Load streaming data from Amazon S3 using AWS Lambda functions as event handlers.
C.Load streaming data from Amazon CloudWatch Logs using AWS Lambda functions as event handlers.
D.Load streaming data from AWS IoT using AWS Lambda functions as event handlers.

Correct Answer – B
You can load streaming data into your Amazon OpenSearch Service domain from many different sources. Some sources, like Amazon Kinesis Data Firehose and Amazon CloudWatch Logs, have built-in support for OpenSearch Service. Others, like Amazon S3, Amazon Kinesis Data Streams, and Amazon DynamoDB, use AWS Lambda functions as event handlers. The Lambda functions respond to new data by processing it and streaming it to your domain.
You can use Lambda to send data to your OpenSearch Service domain from Amazon S3. New data that arrives in an S3 bucket triggers an event notification to Lambda, which then runs your custom code to perform the indexing.
Options A and C are incorrect because they don`t require lambda functions as event handlers to load streaming data.
Kinesis Data Firehose supports OpenSearch Service as a delivery destination.
And you can load streaming data from CloudWatch Logs to your OpenSearch Service domain by using a CloudWatch Logs subscription. 
Option D is incorrect because rules are required instead of lambda functions to load streaming data from AWS IoT.
Rules give your devices the ability to interact with AWS services. Rules are analyzed and actions are performed based on the MQTT topic stream. 
For more information on Amazon Athena, please refer to the following URLs:
https://docs.aws.amazon.com/opensearch-service/latest/developerguide/integrations.html#integrations-s3-lambda
https://docs.aws.amazon.com/opensearch-service/latest/developerguide/integrations.html