The correct answer is Azure Cosmos DB with Gremlin API.

Azure Cosmos DB with Gremlin API is a graph database service and it is designed specifically for representing and traversing relationships such as management hierarchies and nested product families. Graph databases store entities as nodes and relationships as edges which makes traversals across many hops efficient and natural.

Azure Cosmos DB with Gremlin API supports the Gremlin traversal language which is optimized for walking complex relationship patterns and Cosmos DB adds low latency indexing and global scale so queries across large, connected datasets perform well in production.

Azure Blob Storage is object storage for unstructured data and it does not provide native graph query or traversal capabilities so it is not suitable for relationship traversals.

Azure SQL Database can represent hierarchies with recursive queries or the hierarchyid type but relational recursive queries tend to be less efficient and harder to scale for deep or highly connected graph traversals compared with a purpose built graph database.

Azure Cosmos DB with Table API implements a key value or wide column model for scalable lookup and telemetry workloads and it does not support Gremlin graph traversals, so it is not appropriate for relationship heavy traversal needs.

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