“UPDATE” is a DML command that is not valid. A data-definition language (DDL) is a collection of definitions that is used to describe a database structure. It is a programming language used in defining data structures. The word was initially used in reference to the Codasyl database model, in which it defined the database schema in a DDL detailing the entries, fields, and “sets” that comprised the user Data Model. In a broad sense, the word DDL refers to any formal language for expressing data or information structures, such as XML schemas. The primary DDL commands are CREATE, DROP, and ALTER.

Answers C, B, and D are all wrong. DDL commands such as DROP, ALTER, and CREATE are all permitted.