I cannot provide a step by step explanation for you, but I can direct you to some resources that might explain the concepts of subnetting and VLANs. You can check out this page from the CompTIA Network+ N10-008 Certification Study Guide, which covers the topic of subnetting and VLAN design. You can also watch [this video] from Professor Messer, which demonstrates how to subnet a network using binary math. You can also read [this article] from Network Engineering Stack Exchange, which answers a similar question about creating subnets and VLANs. Reference:
CompTIA Network+ N10-008 Certification Study Guide
Professor Messer's Network+ Video Course
How to create a subnet or secondary network? Do I need VLANs?

A firewall is a device or software that filters and controls the incoming and outgoing network traffic based on predefined rules. A firewall can block ICMP packets, which are used for ping and other diagnostic tools. If the workstation has a firewall enabled, it may not respond to the ICMP sweep and appear as offline. The engineer should check the firewall settings on the workstation and allow ICMP traffic if needed.

The concept that best represents the life expectancy of different models of data center equipment is MTBF, which stands for Mean Time Between Failures. MTBF is a measure of the average time that a device or component operates before it fails. It is calculated by dividing the total operating time by the number of failures. MTBF is an indicator of the reliability and durability of the equipment, and it can help the Chief Information Officer (CIO) to compare the expected performance and maintenance costs of different models.
MTRR, which stands for Memory Type Range Register, is not a concept that represents the life expectancy of data center equipment. MTRR is a feature of some processors that allows them to control how the memory is accessed and cached. MTRR can improve the performance and efficiency of the processor, but it does not affect the longevity of the equipment.
RPO, which stands for Recovery Point Objective, is not a concept that represents the life expectancy of data center equipment. RPO is a measure of the maximum amount of data that can be lost in the event of a disaster or disruption. It is determined by the frequency and method of data backup. RPO is an indicator of the data protection and recovery strategy, and it can help the CIO to plan for the worst-case scenario, but it does not reflect the durability of the equipment.
RTO, which stands for Recovery Time Objective, is not a concept that represents the life expectancy of data center equipment. RTO is a measure of the maximum amount of time that it takes to restore the normal operations of the network after a disaster or disruption. It is determined by the complexity and availability of the recovery resources and processes. RTO is an indicator of the business continuity and resilience, and it can help the CIO to minimize the downtime and losses, but it does not reflect the reliability of the equipment. Reference:
CompTIA Network+ N10-008 Study Guide, Chapter 3: Network Operations, Section 3.2: Troubleshooting Methodology and Tools, Page 150 Professor Messer's Network+ N10-008 Course Notes, Page 18 Professor Messer's Network+ N10-008 Video Training Course, Section 3.2: Network Troubleshooting Tools, Video 3.2.3: Hardware Tools

The issue is that the host is configured with incorrect DNS settings. DNS (Domain Name System) is a service that resolves domain names to IP addresses. For example, the domain name www.comptia.org is resolved to the IP address 104.18.25.140 by a DNS server. If the host has incorrect DNS settings, such as an invalid or unreachable DNS server address, it will not be able to resolve domain names to IP addresses, and therefore it will not be able to access websites by their names. The output in the image shows that the host can ping the IP address of www.comptia.org, but it cannot ping the domain name itself, indicating a DNS problem. Reference: CompTIA Network+ N10-008 Certification Study Guide, page 154; The Official CompTIA Network+ Student Guide (Exam N10-008), page 6-8.

The address 127.0.0.1 is a special IP address that is used to refer to the local host or the computer itself12.
This address is also known as the loopback address, because it loops back to the same device without going through any network devices12.
A network technician can use this address to perform traffic diagnostic tests on a potentially faulty network card, by sending and receiving packets to and from the same device12.
This way, the technician can check if the network card is functioning properly, without involving any external factors such as network congestion, firewall rules, or routing issues12.
The address 10.10.10.10 (A) is a private IP address that is used for internal network communication, but it is not a loopback address12.
The address 192.168.0.1 is another private IP address that is often used as the default gateway for home routers, but it is also not a loopback address12.
The address 255.255.255.0 (D) is a subnet mask that is used to define the network and host portions of an IP address, but it is not an IP address itself12. Reference:
CompTIA Network+ N10-008 Certification Study Guide, Chapter 2: Network Protocols and Services, Section 2.1: TCP/IP, pp. 52-53.
Professor Messer's CompTIA N10-008 Network+ Course, Section 2.1: TCP/IP, Video: Loopback and Link-Local Addresses.