To prevent certain files from being tracked by Git, the administrator can use a .gitignore file (B) in the repository. The .gitignore file can specify patterns of files or directories that Git should ignore. This way, the Terraform state files will not appear in the main branch or any other branch. The other commands are not related to this requirement. Reference:
[CompTIA Linux+ Study Guide], Chapter 10: Working with Git, Section: Ignoring Files with .gitignore
[How to Use .gitignore File]

Explanation
The output shows the file access control list (FACL) of the /comptia directory, which is an extension of the standard Linux permissions that allows more fine-grained control over file and directory access1. The FACL consists of two parts: the access ACL and the default ACL. The access ACL applies to the current object, while the default ACL applies to the objects created within the directory2.
The access ACL has three entries: user, group, and other. These are similar to the standard Linux permissions, but they can be specified for individual users or groups as well. The user entry shows that the owner of the directory (root) has read, write, and execute permissions (rwx). The group entry shows that the group owner of the directory (root) has read and execute permissions (r-x). The other entry shows that all other users have no permissions (-).
The default ACL has five entries: user, group, group:wheel, mask, and other. These are applied to any files or directories created within /comptia. The user entry shows that the owner of the new object will have read, write, and execute permissions (rwx). The group entry shows that the group owner of the new object will have read and execute permissions (r-x). The group:wheel entry shows that the members of the wheel group will have read, write, and execute permissions (rwx) on the new object. The mask entry shows that the maximum permissions allowed for any user or group are read, write, and execute (rwx). The other entry shows that all other users will have no permissions (-) on the new object.
Therefore, based on the FACL output, members of the wheel group can read files in /comptia, as they have read permission on both the directory and any files within it. Option B is incorrect because the sticky bit is not set on /comptia or any files within it. The sticky bit is a special permission that prevents users from deleting or renaming files that they do not own in a shared directory3. It is symbolized by a t character in the execute position of others. Option C is incorrect because other users cannot create files in /comptia, as they have no permissions on the directory or any files within it. Option D is incorrect because root is not the only user who can create files in /comptia. Any user who has write permission on the directory can create files within it, such as members of the wheel group.

Explanation
The best command to use to rename the image to match the correct version 2.1.2 is A. docker tag comptia/app:2.1.1 comptia/app:2.1.2. This command will create a new tag for the existing image with the new version number, without changing the image content or ID. The other commands are either incorrect or not suitable for this task. For example:
B: docker push comptia/app:2.1.1 comptia/app:2.1.2 will try to push two images to a remote repository, but it does not rename the image locally.
C: docker rmi comptia/app:2.1.1 comptia/app:2.1.2 will try to remove two images from the local system, but it does not rename the image.
D: docker update comptia/app:2.1.1 comptia/app:2.1.2 will try to update the configuration of a running container, but it does not rename the image.

The issue is that the administrator did not set the default target to graphical.target. A target is a unit of systemd that groups together other units by a common purpose or state. The graphical.target is a target that starts the graphical user interface (GUI) along with other services. The administrator used the command systemctl isolate graphical.target to switch to this target temporarily, but this does not change the default target that is activated at boot time. To make this change permanent, the administrator should have used the command systemctl set-default graphical.target, which creates a symbolic link from /etc/systemd/system/default.target to /usr/lib/systemd/system/graphical.target.
The other options are not correct explanations for the issue. The administrator did reboot the server properly by using systemctl reboot, which shuts down and restarts the system cleanly. The administrator did not need to set the default target to basic.target, which is a minimal target that only starts essential services. The administrator did not shut down the server improperly, which could have caused file system corruption or data loss, but not affect the default target. Reference: systemctl(1) - Linux manual page; How to Change Runlevels (targets) in SystemD

Explanation
The REJECT target sends back an error packet to the source IP address, indicating that the connection is refused by the firewall. This is different from the DROP target, which silently discards the packet without any response. The RETURN target returns to the previous chain, which may or may not accept the connection. The QUEUE target passes the packet to a userspace application for further processing, which is not the desired outcome in this case.
References
CompTIA Linux+ (XK0-005) Certification Study Guide, page 316
iptables - ssh - access from specific ip only - Server Fault, answer by Eugene Ionichev