Which Azure service provides question-answering capabilities from knowledge bases?

Correct answer: Azure Question Answering

Option D is correct because Azure Question Answering (part of Azure AI Language) is the dedicated service that extracts question-and-answer pairs from structured or unstructured content such as FAQs, manuals, and documents to build knowledge base-powered bots and applications. Option A is incorrect because Azure Anomaly Detector is an AI service for detecting anomalies in time-series data, not for building question-answering knowledge bases. Option B is incorrect because Azure Metrics Advisor is a service for monitoring business metrics and detecting issues in metric data, unrelated to question-answering from documents. Option C is incorrect because Azure Video Indexer analyzes video content to extract insights such as transcripts, faces, and topics, and does not provide question-answering from text knowledge bases.