Explanation
The useradd command in Linux is used to create new user accounts on the system1. The -m option tells the command to create the user's home directory as /home/username and copy the files from /etc/skel directory to the user's home directory2. The /etc/skel directory contains the default configuration files for new users3.
Therefore, the command useradd -m tux will add the new user tux and create the user's home directory with default configuration files. The other options are either invalid or do not create the user's home directory.
References:
* Linux Essentials Version 1.6 Objectives, Topic 1.4: Command Line Basics, Subtopic: Basic Shell Commands
* Linux Essentials Version 1.6 Exam Preparation Guide, Section 1.4: Command Line Basics, Page 16
* Linux useradd Command Tutorial for Beginners (15 Examples)