Which combination of AWS services should the company use to build an operationally efficient solution?

Explanations:

Amazon SQS is a fully managed message queue that allows multiple requests to be queued, while AWS Lambda is a serverless compute service that processes requests asynchronously. This combination is efficient for handling large numbers of requests simultaneously.

AWS Data Pipeline is used for data workflow automation and processing, while Amazon EC2 provides compute power. This combination does not efficiently handle hundreds of concurrent requests.

Amazon Kinesis is designed for real-time data streaming and Amazon Athena is for querying data in Amazon S3. This combination is not ideal for managing a large volume of simultaneous user requests.

AWS Amplify and AWS AppSync are designed for building web and mobile applications with real-time data handling, but they are not optimal for processing hundreds of simultaneous user requests.