The special database that always exists after setting up MySQL in a computer is . . . . . . . .

This question asks about a special database that's always present after installing MySQL on your computer. Let's break down the options:
Option A: sampdb - This is not a standard MySQL database.
Option B: mysql - This is the correct answer! The 'mysql' database is essential for managing and configuring your MySQL server. It stores user accounts, permissions, and other crucial information.
Option C: information_schema - This database contains information about other databases within your MySQL setup. It's a helpful resource for understanding your database structure.
Option D: readme_db - This isn't a real database in MySQL.
In conclusion, the 'mysql' database is always there after you install MySQL. It's like the control center for your database system.