Which AWS database service should the company choose?

Explanations:

Amazon DynamoDB is a NoSQL database service, which is suitable for key-value and document data, but it is not designed specifically for graph data or relationships required for a recommendation engine.

Amazon Aurora is a relational database service compatible with MySQL and PostgreSQL, which is not optimized for handling complex graph queries and relationships used in recommendation engines.

Amazon Neptune is a fully managed graph database service optimized for storing and querying highly connected data, making it ideal for recommendation engines that leverage relationships and graph-based data.

Amazon DocumentDB is a document database with MongoDB compatibility, which is suitable for document-oriented data but not optimized for handling graph data required for recommendations.