Port security is the best mitigation technique for preventing an attacker from flooding the MAC address table of network switches. Port security can limit the number of MAC addresses learned on a port, preventing an attacker from overwhelming the switch's MAC table (a form of MAC flooding attack). When the allowed number of MAC addresses is exceeded, port security can block additional devices or trigger alerts.
* Load balancer distributes network traffic but does not address MAC flooding attacks.
* IPS (Intrusion Prevention System) detects and prevents attacks but isn't specifically designed for MAC flooding mitigation.
* NGFW (Next-Generation Firewall) offers advanced traffic inspection but is not directly involved in MAC table security.

A supply chain vendor is a third-party entity that provides goods or services to an organization, such as a SaaS provider. A supply chain vendor can pose a risk to the new system if the vendor has poor security practices, breaches, or compromises that could affect the confidentiality, integrity, or availability of the system or its data. The organization should perform due diligence and establish a service level agreement with the vendor to mitigate this risk. The other options are not specific to the scenario of using a SaaS provider, but rather general risks that could apply to any system.

Software as a Service (SaaS) is the cloud model that best meets the goal of outsourcing the management, including patching, of firmware, operating systems, and applications to the cloud vendor. In a SaaS environment, the cloud provider is responsible for maintaining and updating the entire software stack, allowing the organization to focus on using the software rather than managing its infrastructure.
References = CompTIA Security+ SY0-701 study materials, particularly the domains related to cloud security models.

Software as a Service (SaaS) represents an application that is hosted in the cloud and accessible via the internet from anywhere, with no requirement for on-premises infrastructure. SaaS applications are managed by a third-party provider, allowing users to access them through a web browser, making them highly scalable and flexible for remote access.
References:
* CompTIA Security+ SY0-701 Course Content: Domain 3: Security Architecture, where cloud service models such as SaaS are discussed, highlighting their accessibility and lack of on-premises requirements.

A firewall rule is a set of criteria that determines whether to allow or deny a packet to pass through the firewall. A firewall rule consists of several elements, such as the action, the protocol, the source address, the destination address, and the port number. The syntax of a firewall rule may vary depending on the type and vendor of the firewall, but the basic logic is the same. In this question, the security analyst is creating an inbound firewall rule to block the IP address 10.1.4.9 from accessing the organization's network. This means that the action should be deny, the protocol should be any (or ig for IP), the source address should be 10.1.4.9
/32 (which means a single IP address), the destination address should be 0.0.0.0/0 (which means any IP address), and the port number should be any. Therefore, the correct firewall rule is:
access-list inbound deny ig source 10.1.4.9/32 destination 0.0.0.0/0
This rule will match any packet that has the source IP address of 10.1.4.9 and drop it. The other options are incorrect because they either have the wrong action, the wrong source address, or the wrong destination address. For example, option A has the source and destination addresses reversed, which means that it will block any packet that has the destination IP address of 10.1.4.9, which is not the intended goal. Option C has the wrong action, which is permit, which means that it will allow the packet to pass through the firewall, which is also not the intended goal. Option D has the same problem as option A, with the source and destination addresses reversed.
References = Firewall Rules - CompTIA Security+ SY0-401: 1.2, Firewalls - SY0-601 CompTIA Security+ :
3.3, Firewalls - CompTIA Security+ SY0-501, Understanding Firewall Rules - CompTIA Network+ N10-
005: 5.5, Configuring Windows Firewall - CompTIA A+ 220-1102 - 1.6.