Which optimizer mode does the data dictionary follow?

When responding to this question, you may want to start by defining what the data dictionary is before stating which optimizer mode it follows. This will demonstrate to the interviewer your knowledge of the topic and act as a clarifying statement. While this breaks the rule of keeping your answers to technical questions brief and to the point, it ensures that you are answering the question appropriately and lets the interviewer know you are knowledgeable about this topic.

"Oracle data dictionary is an important component of the Oracle DBMS. The data dictionary stores the metadata, which is all the information about the object's structures, as well as users, tables, columns, and other components. RBO or Rule-Based Optimization is the optimizer mode the data dictionary follows."