According to the Microsoft Azure AI Fundamentals (AI-900) official study materials and Microsoft Learn module “Identify features of common AI workloads,” the Azure Form Recognizer service is part of Azure Cognitive Services for Document Intelligence. It enables organizations to extract, analyze, and identify information from structured and unstructured documents, including sensitive or confidential data such as names, addresses, financial figures, and identification numbers.

Form Recognizer uses optical character recognition (OCR) combined with machine learning to automatically extract key-value pairs, tables, and text fields from documents like invoices, receipts, contracts, and forms. It can be customized to identify and classify documents that contain specific sensitive data, allowing businesses to automate compliance and data governance tasks.

By contrast:

A. Custom Vision is used for image classification and object detection — it analyzes visual data, not document content.

B. Conversational Language Understanding (formerly LUIS) identifies intent and entities in text conversations, not document structure or sensitive data.

Form Recognizer is explicitly mentioned in the AI-900 course as the tool for document analysis and extraction. It can even integrate with Azure Cognitive Search or Azure Purview for further data management and compliance workflows.

Therefore, the verified and correct answer, aligned with Microsoft’s official training content, is C. Form Recognizer, as it is the Azure Cognitive Service capable of identifying and processing documents containing sensitive information.