MySQL Subsystems: Execution Engine, Query Preprocessor, and DDL Compiler

All of the options are part of the MySQL subsystem. These include:

• 'Execution Engine': Responsible for executing the query plan generated by the query optimizer.
• 'Query Preprocessor': Parses and validates SQL queries before they are passed to the optimizer.
• 'DDL Compiler': Compiles data definition language (DDL) statements, such as CREATE TABLE and ALTER TABLE, into internal database structures.