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
A spectrum analyzer is a device that can measure the signal strength and frequency of wireless networks. It can help troubleshoot wireless NIC issues by identifying interference, channel overlap, or signal degradation.
A hotspot is a wireless access point that provides internet access to mobile devices. Near-field communication is a technology that allows two devices to communicate wirelessly when they are in close proximity. An Ethernet tap is a device that can monitor network traffic on an Ethernet cable by creating a copy of the data without affecting the original transmission. References: https://www.comptia.org/certifications/a#examdetails
https://www.comptia.org/blog/what-is-a-spectrum-analyzer

Explanation
A router (option C) is a network device that is used to separate broadcast domains. A broadcast domain is a logical division of a computer network in which all nodes can reach each other by broadcast at the data link layer. Routers operate at the network layer of the OSI model and use routing tables to determine the best path for forwarding packets between different networks.
By separating broadcast domains, routers can help to reduce network congestion and improve performance.
When a router receives a broadcast packet on one of its interfaces, it does not forward the packet to any other interfaces. This means that only devices within the same broadcast domain as the sender will receive the broadcast packet.

Explanation
Cat 5 cable is limited to a maximum data transfer rate of 100Mbps, while Cat 5e, Cat 6, and Cat 6a cables support Gigabit Ethernet (1000Mbps) and higher speeds. Even though the LAN card is capable of Gigabit speeds, it cannot achieve that speed when using a Cat 5 cable. Upgrading to a Cat 5e or higher cable would allow the computer to achieve Gigabit speeds. References: CompTIA A+ Certification Exam: Core 1 - Page
196

Explanation
The technician should install the appropriate printer drivers for the OS to enable the computer to communicate with the printer. The generic printer name suggests that the drivers are missing or not installed correctly.