Which service provides on-demand translation using advanced machine learning?

The correct choice is Amazon Translate, which is a fully managed service that provides high-quality language translation using advanced machine learning models. This service allows for real-time text translation across a variety of languages, enabling applications to reach a global audience by communicating in multiple languages.

Amazon Translate is especially useful for developers looking to localize content or provide multilingual support without the need for extensive language expertise or additional resources. It automatically detects the source language of the text and translates it into the desired target language, making it a powerful tool for enhancing accessibility and user experience in applications.

Other services listed in the options serve different purposes: Amazon Polly is focused on converting text into spoken audio using text-to-speech technology, allowing developers to add voice capabilities to applications. Amazon Rekognition specializes in analyzing images and videos to identify objects, people, and scenes, primarily for computer vision tasks. Amazon Comprehend is designed for natural language processing, providing capabilities for sentiment analysis, entity recognition, and language understanding. Each of these services offers unique functionalities, but when specifically looking for on-demand translation powered by machine learning, Amazon Translate is the appropriate choice.