What service is used to reliably capture, transform, and deliver streaming data?

The correct answer is Amazon Kinesis Data Firehose because it is specifically designed for capturing, transforming, and delivering streaming data to various destinations in real-time. This service enables users to easily load streaming data into data lakes, data stores, and analytics services without having to manage the underlying infrastructure.

Amazon Kinesis Data Firehose provides automatic scaling and is highly reliable, making it suitable for applications that require real-time processing of streaming data, such as log and event data collection. It allows users to transform the streaming data on the fly by applying functions, such as data format conversion or filtering, before storing it in the designated outputs.

In contrast, AWS Data Pipeline is primarily used for processing and transferring data between different AWS services on a scheduled basis rather than in real-time, which doesn't align with the requirement for capturing and delivering streaming data. AWS Step Functions is a service for coordinating distributed applications and microservices through workflows, mostly dealing with orchestrating processes rather than specifically handling streaming data. AWS Glue is primarily an ETL (Extract, Transform, Load) service for preparing and loading data for analytics but is not tailored to the real-time streaming data delivery the question asks about.