What is the special database that always exists after setting up MySQL on a computer?

This question is asking about a database that is automatically created when you install MySQL on your computer. This database is essential for managing and accessing information about your MySQL server.

Let's look at the options:

Option A: sampdb - This is not a standard database in MySQL.
Option B: mysql - This is the correct answer! The mysql database is a special database that is always created when you set up MySQL. It stores information about users, permissions, and other important configuration settings.
Option C: information_schema - This database is also important, but it's not automatically created during installation. It's a special database that contains information about the structure of your other databases and tables.
Option D: readme_db - This is not a real database in MySQL.

Therefore, the answer is Option B: mysql.