A split tunnel VPN solution would allow secure, remote access for sales staff to the CRM application without impacting videoconferencing traffic. A VPN stands for virtual private network, which is a secure connection between two or more devices over a public network, such as the internet. A VPN encrypts and authenticates the data, ensuring its confidentiality and integrity. A split tunnel VPN is a type of VPN that allows some traffic to go through the VPN tunnel, while other traffic goes directly to the internet. This can improve performance and bandwidth utilization by reducing unnecessary encryption and routing overhead. By using a split tunnel VPN, sales staff can access the CRM application that connects to a database server in the corporate data center through the VPN tunnel, while using online videoconferencing services through their local internet connection. Reference: [CompTIA Network+ Certification Exam Objectives], What Is Split Tunneling? | NordVPN

A site-to-site VPN is a type of VPN that connects two or more remote offices securely over an untrustworthy network, such as the Internet. A site-to-site VPN allows each office to access network shares and resources at the other site, as if they were on the same local network. A site-to-site VPN encrypts and tunnels the traffic between the offices, ensuring privacy and integrity of the data. Reference: https://www.comptia.org/blog/what-is-a-site-to-site-vpn

The DHCP network scope defines the range of IP addresses that can be assigned to the devices on the network by the DHCP server.
In this scenario, the DHCP scope is configured for 244 addresses, which is not enough for the 325 loT sensors that need to connect to the network.
Therefore, the first 244 loT sensors were able to get an IP address from the DHCP server and connect to the TFTP server, while the remaining 81 sensors could not obtain an IP address and were shown as offline.
To solve this problem, the network administrator should check the DHCP network scope and either increase the range of IP addresses or create a new scope for the additional loT sensors.
Checking the gateway connectivity to the TFTP server, the NTP server status, or the loT devices for hardware failure are not relevant to this issue, as they would affect all the loT sensors, not just some of them. Reference:
[CompTIA Network+ N10-008 Study Guide], Chapter 2: Network Devices and Technologies, Section 2.3: Configure and Support loT Devices, p. 84
[Professor Messer's CompTIA N10-008 Network+ Course Notes], Section 1.2: Network Topologies and Types, p. 8 Network+ N10-008 Practice Test | CertBlaster, Question 1

Single-mode fiber is a type of optical fiber that has a small core diameter and allows only one mode of light to propagate. This reduces signal attenuation and increases transmission distance, making it suitable for long-distance communication networks. Single-mode fiber can carry data over thousands of kilometers without requiring repeaters or amplifiers. Single-mode fiber is also immune to electromagnetic interference and has a higher bandwidth than multimode fiber. Therefore, single-mode fiber is the best cable type for connecting sites on multiple continents. Reference: [CompTIA Network+ Certification Exam Objectives], [Single-mode optical fiber - Wikipedia] Single-mode fiber optic cable uses a single ray of light to transmit data. This allows it to achieve very low attenuation and high bandwidth.
Multimode fiber optic cable uses multiple rays of light to transmit data. This results in higher attenuation and lower bandwidth than single-mode cable.
Twisted pair copper cable uses two insulated copper wires to transmit data. It is less expensive than fiber optic cable, but it has higher attenuation and lower bandwidth.
When choosing a cable type for a long-distance application, it is important to consider the following factors:
Attenuation: The amount of signal loss that occurs over the length of the cable.
Bandwidth: The amount of data that can be transmitted over the cable per second.
Cost: The cost of the cable and installation.
Single-mode fiber optic cable is the best choice for long-distance applications because it has the lowest attenuation and highest bandwidth of any cable type. However, it is also the most expensive cable type.

Port mirroring is a feature that allows a switch to copy the traffic from one or more ports to another port for monitoring or analysis purposes. Port mirroring can help a network administrator to troubleshoot network problems, detect security threats, or optimize network performance. Port mirroring can be configured on most switches using the command-line interface (CLI) or a graphical user interface (GUI).
Reference:
CompTIA Network+ N10-008 Certification Exam Objectives, page 51
CompTIA Network+ N10-008 Cert Guide, Chapter 11: Switching Technologies Port Mirroring - CompTIA Network+ Certification (N10-008): The Total Course [Video]1 CompTIA Network+ N10-005: 2.1 - Port Mirroring - Professor Messer IT Certification Training Courses2 CompTIA Network+ N10-005: 1.4 - Port Mirroring3