Which of the following components in a DBMS is used to maintain the data dictionary?

The correct choice relates to the data definition component of a database management system (DBMS) because this component specifically involves defining and managing the structure of the database. This includes the creation, alteration, and deletion of database schemas, tables, and relationships, all of which are essential for maintaining the data dictionary. The data dictionary itself is a metadata repository that contains definitions of data elements and their relationships within the database, ensuring data integrity and facilitating efficient data management.

Data definition languages (DDL) are utilized to perform operations that affect the data dictionary, which holds critical information about database structure, including data types, constraints, and descriptions of how data is organized. Therefore, the role of data definition in overseeing and updating the data dictionary makes it central to maintaining the integrity and usability of the database.

In contrast, other components such as data manipulation primarily focus on the retrieval and modification of the actual data contained in the database, while the database engine is concerned with executing database operations and managing storage. Application generation pertains to the tools used to create user interfaces and applications that interact with the database, which does not directly involve managing the data dictionary.