Explanation
The inbound rule that the security team identified as a potential vulnerability is the one that allows SSH access (port 22) from any source (0.0.0.0/0). This means that anyone on the internet can try to connect to the Linux servers using SSH, which poses a risk of unauthorized access or brute-force attacks. The cloud administrator, who is working remotely, logs in to the cloud management console and modifies the rule to set the source to
"My IP". This means that only the administrator's IP address can connect to the Linux servers using SSH, which improves the security of the servers. However, this also prevents other authorized users, such as the internal developer, from accessing the servers using SSH, as they have different IP addresses than the administrator. Therefore, the administrator needs to modify the rule again to allow more sources for SSH access.
The best option for both the developer and the administrator to access the server from their locations is to modify the inbound rule to allow the company's external IP address as a source. This means that only the IP addresses that belong to the company's network can connect to the Linux servers using SSH, which reduces the attack surface and ensures that only authorized users can access the servers. The company's external IP address can be obtained by using a web service such as [What Is My IP Address?] or [IP Location]. The administrator can then enter this IP address or its CIDR notation in the source field of the inbound rule.

Explanation
Configuring a firewall rule to block the traffic on the affected instance is what the administrator should perform during the containment phase of a security incident in the cloud. A security incident is an event or situation that affects or may affect the confidentiality, integrity, or availability of cloud resources or data. A security incident response is a process of managing and resolving a security incident using various phases, such as identification, containment, eradication, recovery, etc. The containment phase is where the administrator tries to isolate and prevent the spread or escalation of the security incident. Configuring a firewall rule to block the traffic on the affected instance can help to contain a security incident by cutting off any communication or interaction between the instance and other systems or networks, which may stop any malicious or unauthorized activity or access.

Explanation
The best options to implement for a public cloud solution for an existing application using lift and shift that requires scalability and external access are a load balancer and a VPN (virtual private network). A load balancer is a device or service that distributes incoming traffic across multiple servers or instances based on various criteria, such as availability, capacity, or performance. A load balancer can improve scalability by balancing the workload and optimizing resource utilization. A VPN is a technology that creates a secure and encrypted connection over a public network, such as the internet. A VPN can provide external access by allowing remote users or sites to connect to the cloud resources as if they were on the same private network.
Reference: CompTIA Cloud+ Certification Exam Objectives, Domain 1.0 Configuration and Deployment, Objective 1.4 Given a scenario, execute a provided deployment plan.