The category of SQL commands that is required to revoke access to database objects is DCL. DCL, or Data Control Language, is a subset of SQL commands that are used to control or manage the access or permissions of users or roles on a database. DCL includes commands such as GRANT and REVOKE. GRANT is a DCL command that is used to grant privileges or roles to users or roles on specific objects in a database, such as tables, views, procedures, etc. REVOKE is a DCL command that is used to revoke privileges or roles from users or roles on specific objects in a database. For example, the following statement uses the REVOKE command to revoke the SELECT privilege from user Alice on table employee:

REVOKE SELECT ON employee FROM Alice;

The other options are either different categories of SQL commands or not related to SQL commands at all. For example, IDDL is not a valid acronym or category of SQL commands; IDML is not a valid acronym or category of SQL commands; TCL, or Transaction Control Language, is a subset of SQL commands that are used to control or manage transactions on a database, such as committing or rolling back changes. References: CompTIA DataSys+ Course Outline, Domain 4.0 Data and Database Security, Objective 4.2 Given a scenario, implement security controls for databases.