Exam XK0-005 topic 1 question 221 discussion

So the root login is administratively locked. With *LOCK* in the password field, it means that nobody can log into the system as root user using a password. If the root account was configured for other authentication methods, like SSH keys or certificates, they could do so that way. That alone would not prevent regular users the ability to run "sudo", if they are configured properly in /etc/sudoers. That is because "sudo" uses the user's password, not the root password. But, the sudoers file is misconfigured, maybe someone tried editing it directly with "vim" rather than "visudo" and broke it. Now it seems that nobody can perform sudo and nobody can log in as root (thus, no permission to fix the sudoers file). A good course of action is to boot into single user mode, which would allow root access to a simplified system without a password, and fix the syntax error.