Which command is used in Mysql command line tool to return to window command shell?

Answer: Option C

This question is about how to leave the MySQL command line tool and go back to your regular operating system's command prompt (like Windows Command Prompt or Linux terminal).

Think of the MySQL command line tool as a special program you enter to talk to your database. When you're done, you want to exit that program and go back to your regular command prompt.

In MySQL, both "exit;" and "quit;" commands achieve this. They both do the same thing: tell MySQL to stop and return you to your regular command prompt.

So, the correct answer is Option C: both exit; and quit;