The prebuilt receipt model is part of Azure AI Document Intelligence (formerly Form Recognizer), which belongs to the broader Azure AI Services family. The prebuilt receipt model is designed to automatically extract key information such as merchant names, dates, totals, and tax amounts from receipts without requiring custom training.

Among the given options, C. Azure AI Services is correct because it encompasses all cognitive AI capabilities—vision, language, speech, and document processing. Specifically, Azure AI Document Intelligence is included within Azure AI Services and provides both prebuilt and custom models for processing invoices, receipts, business cards, and identity documents.

Options A (Computer Vision) and D (Custom Vision) are image-based services, not form-processing tools. Option B (Azure Machine Learning) focuses on building custom predictive models, not using prebuilt document models.

Therefore, the correct answer is C. Azure AI Services, which includes the prebuilt receipt model in Document Intelligence.