If users are experiencing decreased bandwidth and connectivity issues in a Wi-Fi mesh network, the technician should use a Wi-Fi analyzer to determine whether the channel in use is overcrowded and to identify which channel the mesh network should use for best performance. References: CompTIA A+ Certification Study Guide, Tenth Edition, pg. 308

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.

Explanation
The 802.11ax protocol, also known as Wi-Fi 6, provides the fastest bandwidth among the options listed. It can achieve up to 10 Gbps of data transfer rate, using technologies such as OFDMA, MU-MIMO, and 1024-QAM.
The 802.11ac protocol, or Wi-Fi 5, is the second fastest, with a maximum of 3.46 Gbps, followed by the
802.11n protocol, or Wi-Fi 4, with a maximum of 600 Mbps. The 802.11a protocol is the slowest, with a maximum of 54 Mbps
https://www.lifewire.com/wireless-standards-802-11a-802-11b-g-n-and-802-11ac-816553

Infrastructure as a service (IaaS) is a means of provisioning IT resources, such as servers, load balancers, and storage area network (SAN) components, quickly. Rather than purchase these components and the Internet links they require, you deploy them as needed from the service provider's datacenter.
IaaS would allow for robust storage and computational solutions without having to manage physical servers.