A damaged cable is most likely the cause of the desktop not connecting to the network. A damaged cable can cause physical layer issues such as loss of signal, attenuation, interference, or crosstalk. These issues can prevent the desktop from establishing a link with the switch and result in the LED status light on the switchport being off. Other possible causes of physical layer issues are faulty connectors, ports, or transceivers. Reference: https://www.cisco.com/c/en/us/support/docs/lan-switching/ethernet/14119-37.html

Layer 4 is where TCP/IP port numbers identify which network application is receiving the packet and where it is applied. Layer 4 is also known as the transport layer in the TCP/IP model or the OSI model. The transport layer is responsible for providing reliable or unreliable end-to-end data transmission between hosts on a network. The transport layer uses port numbers to identify and multiplex different applications or processes that communicate over the network. Port numbers are 16-bit numbers that range from 0 to 65535 and are divided into three categories: well-known ports (0-1023), registered ports (1024-49151), and dynamic ports (49152-65535). Some examples of well-known port numbers are 80 for HTTP, 443 for HTTPS, and 25 for SMTP. Reference: [CompTIA Network+ Certification Exam Objectives], Transport Layer - an overview | ScienceDirect Topics

The situation in which an employee knowingly allows someone access to a restricted area without verifying authentication is called Tailgating. Here's why:
Piggybacking (Option A) refers to an unauthorized person following an authorized person into a secure area without their knowledge.
Shoulder surfing (Option C) involves someone observing sensitive information (such as passwords) by looking over another person's shoulder.
Phishing (Option D) is a form of social engineering where attackers deceive individuals into revealing confidential information.
Therefore, the correct answer is B. Tailgating

To find all devices connected within a network, a technician can use an IP scanner. An IP scanner sends a ping request to all IP addresses within a specified range and then identifies the active devices that respond to the request.

Multifactor authentication is a method of verifying a user's identity by requiring more than one factor, such as something the user knows, something the user has, or something the user is. A password is something the user knows, and a fingerprint is something the user is. Therefore, a user who needs to enter a password and scan a fingerprint is using multifactor authentication.