Which AWS service will meet these requirements?

Explanations:

Amazon Kendra is a highly accurate and intelligent search service that allows for searching across multiple data sources, including documents stored in Amazon S3. It uses machine learning to understand the content and context of documents, making it suitable for text search requirements.

Amazon Rekognition is primarily used for image and video analysis, enabling features like object detection, facial recognition, and text detection in images. It does not provide capabilities for searching text within documents stored in S3.

Amazon Polly is a text-to-speech service that converts text into lifelike speech. While it can process text, it does not have functionalities for searching text within documents or providing search capabilities in S3.

Amazon Lex is a service for building conversational interfaces using voice and text. It is designed for creating chatbots and voice assistants, not for searching text within documents stored in S3.