The technician will need to connect the DVI port on the computer to the new display's HDMI port. To do this, a DVI to HDMI cable will be needed. This type of cable will allow the computer's DVI video signal to be transmitted to the new display's HDMI port.
A digital-to-analog converter (DAC) is used to convert a digital signal to an analog signal. An A/V switcher is used to switch between multiple audio and video sources and display them on a single monitor or display. A DisplayPort to HDMI adapter is used to convert a DisplayPort signal to an HDMI signal, but it is not necessary in this scenario as the computer has a DVI port and not a DisplayPort.

DDR3 is the most commonly used RAM type in modern desktop computers. It is faster and more energy efficient than its predecessors, and offers larger capacity modules. Reference: CompTIA A+ Certification Exam Guide, Ninth Edition, Chapter 5

This is a safe and sensible option if you value your data more than anything else. You don't want to risk losing your data by trying other methods that may worsen the situation. You can use a software tool or a service provider to recover your data before attempting any repairs.

A cable tester and a crimper are the best tools to execute the task of replacing all RJ45 cables in a customer environment. A cable tester can be used to check the continuity and quality of a cable, and a crimper can be used to attach RJ45 connectors to the ends of a cable. An optical fiber tester is a tool that can be used to test fiber optic cables, which are not RJ45 cables. Scissors are not a tool for replacing cables, but for cutting them. A coaxial cable is a type of cable that has a single copper conductor at its center, which is not an RJ45 cable either. A screwdriver is not a tool for replacing cables, but for fastening or loosening screws.

A hotspot is a wireless access point that provides internet access to devices that are connected to it. The technician can use a hotspot to check if the laptop's wireless NIC is functional by connecting the laptop to the hotspot and then trying to browse the internet. If the laptop is able to browse the internet, then the wireless NIC is functional.
Near-field communication (NFC) is a wireless technology that allows two devices to communicate with each other when they are in close proximity. NFC is not typically used to check if a wireless NIC is functional.
An Ethernet tap is a device that is used to monitor network traffic. An Ethernet tap is not typically used to check if a wireless NIC is functional.
A spectrum analyzer is a device that is used to measure the frequency spectrum of a signal. A spectrum analyzer is not typically used to check if a wireless NIC is functional.
Therefore, the correct answer is A. Hotspot.