To create a transparent table in the ABAP Dictionary, the user must perform several steps. However, only one of these steps automatically creates the table in the underlying database.

The user needs to know that transparent tables are used to store data in the database and can be accessed using SQL commands.

Now, let's go through each option and explain why it is right or wrong:

A. Adding technical settings to the table: This step is necessary in order to define the structure of the table, such as the fields and their data types, keys, and other technical settings. However, it does not automatically create the table in the database.

B. Checking the table syntax: This step checks the syntax of the table definition and ensures that it is valid. It does not create the table in the database.

C. Saving the table: This step saves the table definition in the ABAP Dictionary, but it does not create the table in the database.

D. Activating the table: This step automatically creates the table in the underlying database. When the user activates the table, the system generates the SQL code to create the table and execute it in the database.

Therefore, the correct answer is:

The Answer is: D