You need to store millions of small JSON documents (each ~1 KB) that are frequently updated by multiple concurrent users. You require low-latency access to individual documents. Which Azure Storage solution should you use?
Table Storage is a NoSQL store designed for large quantities of small entities with partition key and row key, ideal for this scenario.
Why this answer
Azure Table Storage is a NoSQL key-value store optimized for storing large volumes of structured, non-relational data with low-latency access by partition key and row key. It supports millions of small JSON documents (~1 KB) and handles frequent concurrent updates via optimistic concurrency control using ETags, making it ideal for this scenario.
Exam trap
The trap here is that candidates often choose Azure Cosmos DB for NoSQL because it is a more feature-rich document database, but the question emphasizes cost-effectiveness and simplicity for high-volume, low-latency key-value access, which is exactly where Azure Table Storage excels.
How to eliminate wrong answers
Option A is wrong because Azure Blob Storage with Block blobs is designed for large, unstructured binary or text objects (up to ~4.7 TB per blob) and does not provide native key-value lookup for individual small documents; it also lacks built-in optimistic concurrency for frequent updates by multiple users. Option C is wrong because Azure Files with SMB protocol provides file-level access with network shares, not a document store; it introduces protocol overhead and is not optimized for low-latency access to millions of individual small JSON documents. Option D is wrong because Azure Cosmos DB for NoSQL, while capable of storing JSON documents, is a premium, globally distributed database service with higher cost and complexity; for this specific requirement of millions of small, frequently updated documents with low-latency access, Azure Table Storage is the more cost-effective and purpose-built solution.