The PAM module pam_nologin.so will prevent logins from accounts other than root, while the file /etc
/nologin exists. This module checks for the existence of the file /etc/nologin and displays its contents to the user before denying access. The root user is exempt from this check and can still log in. This is the correct module to accomplish the task. The other options are incorrect because they are either non-existent modules (pam_login.so or pam_logindef.so) or do not perform the required function (pam_access.so controls access based on host, user, or time). References: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter
15: Managing Users and Groups, page 471.

rpm -qa lists all installed packages and filtering with perl will show if Perl is installed or not. This command is useful for verifying prerequisites like the presence of certain software on the system.

The -i option stands for 'interactive' and it prompts before overwriting any existing files. This ensures that no existing files are accidentally overwritten during the move operation.

The language that the playbook should be written in is YAML. YAML stands for YAML Ain't Markup Language, which is a human-readable data serialization language. YAML is commonly used for configuration files and data exchange. YAML uses indentation, colons, dashes, and brackets to represent the structure and values of the data. YAML also supports comments, variables, expressions, and functions. Ansible is an open-source tool for automating tasks and managing configuration on Linux systems. Ansible uses YAML to write playbooks, which are files that define the desired state and actions for the systems. Playbooks can be used to automate the installation of patches on several Linux systems by specifying the hosts, tasks, modules, and parameters. The language that the playbook should be written in is YAML. This is the correct answer to the question. The other options are incorrect because they are not the languages that Ansible uses for playbooks (SQL, HTML, or JSON). Reference: CompTIA Linux+ (XK0-005) Certification Study Guide, Chapter 18: Securing Linux Systems, page 549.