Which of the following features were added to the ABAP Dictionary to support the SAP HANA database?

The correct answer is the definition of full-text indexes. This feature was specifically introduced in the ABAP Dictionary to leverage the capabilities of the SAP HANA database. Full-text indexing allows for efficient searching and retrieval of data based on text content within fields, which is especially beneficial for applications dealing with large amounts of textual data. By enabling full-text indexing, developers can create queries that are optimized for performance, making use of the underlying HANA architecture.

Regarding the other choices, while they may relate to other functionalities within ABAP or various database concepts, they do not specifically address enhancements added to support the SAP HANA database in the same way. The changes of data class refer to the storage parameters for tables, de-pooling and de-clustering focus on how data is organized in memory for performance, and the definition of an enhancement category pertains to extendability aspects of ABAP. Each of these may play a role in the development environment, but they do not relate directly to the specific enhancements made to accommodate the capabilities of SAP HANA like the full-text indexing feature does.