What type of database is Amazon DynamoDB?
In-memory
Relational
Key-value
Graph
Explanations:
Amazon DynamoDB is not an in-memory database; it is a managed NoSQL database service.
DynamoDB is not a relational database; it does not use fixed schemas or SQL.
DynamoDB is primarily a key-value store, allowing for high-speed data retrieval using keys.
DynamoDB does not fit the graph database model; it does not focus on relationships between entities like graph databases do.
It seems to me that the answer is:
Key-value