Which of the following AWS services is focused on data exchange?

The focus of AWS Data Exchange is specifically on facilitating data sharing and exchange among different parties. It provides a platform where data providers can publish their data products and data consumers can subscribe to these products seamlessly. AWS Data Exchange simplifies the process of finding, subscribing to, and using third-party data in the cloud, covering various use cases across industries, such as analytics, machine learning, and data enrichment.

In comparison, Amazon Redshift is a fully managed data warehousing service that enables you to run complex queries against massive datasets but does not specialize in data exchange. AWS Glue is a data integration service geared towards preparing and loading data for analytics, rather than facilitating the exchange of data. Amazon DynamoDB is a fully managed NoSQL database service focused on providing fast and predictable performance for applications but is not intended specifically for data exchange between different entities. Thus, the primary purpose and capabilities of AWS Data Exchange make it the most relevant service in the context of data exchange among the given options.