Answer: Key-value

Amazon DynamoDB is a fully managed NoSQL database service that provides fast and predictable performance with seamless scalability. It is specifically designed as a key-value and document database. **Key characteristics of DynamoDB:** - **Key-value store**: Data is stored as items (similar to rows) with a primary key that uniquely identifies each item - **Document database**: Supports JSON-like documents with nested attributes - **NoSQL**: Non-relational, schema-less design - **Serverless**: Fully managed with automatic scaling - **High performance**: Single-digit millisecond latency **Why other options are incorrect:** - **In-memory**: While DynamoDB can use in-memory caching through DAX (DynamoDB Accelerator), it is not primarily an in-memory database like Amazon ElastiCache for Redis - **Relational**: Relational databases use structured tables with rows and columns and SQL queries (like Amazon RDS) - **Graph**: Graph databases are designed for relationships between data points (like Amazon Neptune)

Author: Ritesh Yadav