This issue is directly related to SELinux enforcement, which is a key topic in the Security domain of CompTIA Linux+ V8. The logs clearly indicate that SSH key-based authentication is failing due to an SELinux access control violation rather than a traditional file permission or SSH configuration problem.
The most important clue is the AVC denial message, which shows that the sshd process is being denied read access to the authorized_keys file. The security context of the file is listed as unconfined_u:object_r:
home_root_t:s0. Under a targeted SELinux policy, SSH is only permitted to read authorized_keys files that are labeled with the correct SELinux type, typically ssh_home_t.
Because SELinux is running in enforcing mode, it actively blocks access that violates policy rules, even if standard UNIX permissions are correct. Although the file permissions (600) are acceptable for an authorized_keys file, SELinux does not rely solely on traditional permissions. The mismatch between the expected SELinux context and the actual context prevents sshd from accessing the file, causing SSH to fall back to password authentication.
Option D correctly identifies the root cause: the authorized_keys file does not have the correct SELinux security context. This is a well-documented Linux+ V8 troubleshooting scenario, commonly resolved by restoring the correct context using commands such as restorecon or by ensuring the file resides in a properly labeled home directory.
The other options are incorrect. Restarting sshd does not fix SELinux labeling issues. The policy itself is functioning as intended, and file ownership alone does not override SELinux access controls.
Linux+ V8 documentation emphasizes that SELinux denials must be addressed by correcting file contexts rather than weakening security controls. Therefore, the correct answer is D.

The fuser command identifies and terminates processes that are actively using the /data filesystem, allowing it to be safely unmounted once those processes are stopped.

The correct answer is B. top because it provides a dynamic, real-time view of running processes and system resource usage. The top command is an essential Linux system monitoring utility that continuously updates information about CPU usage, memory consumption, running processes, load averages, and system uptime. It is widely used by system administrators for performance monitoring and troubleshooting.
When executed, top displays a full-screen interface showing active processes sorted by resource usage (typically CPU by default). It updates at regular intervals, allowing administrators to observe changes in real time. Additionally, it offers interactive features such as sorting processes, killing processes, and filtering output, which enhances system management capabilities.
Option A (ps) is incorrect because although it lists running processes, it provides only a snapshot at a specific moment in time. It does not update dynamically unless repeatedly executed or combined with other tools.
Option C (df) is incorrect because it displays disk space usage of filesystems, not running processes.
Option D (free) is incorrect because it shows memory usage statistics, including total, used, and available memory, but does not display process-level activity.
From a Linux+ perspective, understanding tools like top is crucial under System Management objectives. It enables administrators to monitor system health, identify resource-intensive processes, and take corrective actions when necessary. Real-time monitoring is particularly important in production environments where performance issues must be diagnosed and resolved quickly.

Comprehensive and Detailed Explanation From Exact Extract:
The lsscsi command is used to list information about SCSI devices (including storage arrays) that are attached to the system. This is critical when integrating a new storage array because it allows the administrator to verify that the operating system detects the new device at the SCSI layer, which is the underlying interface for most enterprise storage solutions. lsscsi outputs a list of recognized SCSI devices, their device nodes, and associated information.
Other options:
B). lsusb: Lists USB devices, not storage arrays on SCSI/SATA/SAS.
C). lsipc: Displays information on IPC (inter-process communication) facilities, unrelated to hardware detection.
D). lshw: Lists hardware details and can show storage, but lsscsi is specifically designed for SCSI device detection and is the most direct method for this task.
Reference:
CompTIA Linux+ Study Guide: Exam XK0-006, Sybex, Chapter 7: " Managing Storage " , Section: " Identifying and Accessing Storage Devices " CompTIA Linux+ XK0-006 Objectives: Domain 4.0 - Storage and Filesystems

Container lifecycle management is a core topic within the Automation, Orchestration, and Scripting domain of CompTIA Linux+ V8. Administrators must understand the difference between creating containers, starting containers, and executing commands within running containers.
The correct command is docker run -it app-01-image. The docker run command performs three actions at once: it creates a new container from the specified image, starts the container, and optionally attaches the administrator's terminal to it. The -i option keeps standard input open, while the -t option allocates a pseudo- terminal (TTY). Together, these options allow the administrator to interactively connect to the container immediately after it is created.
The other options are incorrect for the following reasons. docker start is used only to start an existing stopped container and does not create a new container from an image. Additionally, -t and -d are not valid options for attaching an interactive terminal during container startup. docker build is used to build a Docker image from a Dockerfile and cannot be used to create or connect to a container. docker exec is used to run commands inside an already running container and therefore cannot be used to create a container.
Linux+ V8 documentation emphasizes that docker run is the primary command used when administrators want to instantiate containers from images and interact with them. This command is commonly used during testing, development, and troubleshooting workflows.