Explanation
The correct answer is C. PoE switch.
A PoE switch is a network device that can provide both data and power to other devices over an Ethernet cable. PoE stands for Power over Ethernet, which is a technology that allows electrical power to be transmitted along with data on twisted pair Ethernet cabling. This eliminates the need for separate power supplies or AC adapters at the users' desks, as the VoIP devices can receive power from the PoE switch12.
A firewall is a network device that monitors and controls incoming and outgoing network traffic based on predefined security rules. It does not provide power to other devices1.
A power injector is a device that adds electrical power to an Ethernet cable for a single device. It is not suitable for a large number of devices, as it would require one power injector per device1.
A router is a network device that connects multiple networks and forwards data packets between them. It does not provide power to other devices1.

Explanation
The black smudges over the entire image on a printed receipt are most likely caused by a jammed ribbon that is rubbing on the paper. The solution is to clear the bad ribbon and feed it through the printer properly. Ribbon jams can be caused by various issues, such as incorrect installation or a damaged ribbon. References:
CompTIA A+ Certification Exam Objectives - 220-1001: 4.5 Given a scenario, troubleshoot common printer problems.

Explanation
By documenting the findings, action, and outcomes of issues, the technicians can create a knowledge base that can be used to resolve similar issues in the future more quickly and efficiently. The documentation can also help identify patterns or trends that can lead to preventive measures or root cause analysis. Documenting the issues can also improve communication and collaboration among technicians and users, as well as provide evidence of service quality and performance. Reference:
https://partners.comptia.org/docs/default-source/resources/a-core-1-content-guide (page 4)

Explanation
A public cloud is a cloud computing model that provides services and resources to anyone over the internet.
The service that the user uploads a file to is an example of a public cloud service, as it is accessible via a web browser and a client application, allows multiple users to access the file, and is provided by a third party for a monthly fee. A hybrid cloud is a combination of public and private cloud services that share data and resources. Infrastructure as a service is a cloud computing model that provides servers, storage, networking, and software over the internet. Private cloud is a cloud computing model that provides services and resources to a specific organization or group over a private network