Explanation
The port that should be disabled on the firewall is port 3389. Port 3389 is used by Remote Desktop Protocol (RDP), which is a protocol that allows remote access and control of a Windows system through a graphical user interface. RDP can pose a security risk if it is not properly configured or secured, as it can expose the system to unauthorized or malicious access from external sources. Therefore, port 3389 should be disabled on the firewall unless it is needed for legitimate purposes.
References: CompTIA Server+ SK0-005 Certification Study Guide, Chapter 3, Lesson 3.3, Objective 3.3

Explanation
The most likely issue that prevents the newly added server from seeing any of the LUNs on the SAN is that a single-mode fiber cable is used in place of multimode. A single-mode fiber cable is a type of optical fiber cable that has a small core diameter and allows only one mode of light to propagate through it. A single-mode fiber cable can transmit data over long distances at high speeds, but it requires more expensive transceivers and connectors than multimode fiber cables. A multimode fiber cable is a type of optical fiber cable that has a larger core diameter and allows multiple modes of light to propagate through it. A multimode fiber cable can transmit data over short distances at lower speeds than single-mode fiber cables, but it is more compatible and cost-effective than single-mode fiber cables. If a single-mode fiber cable is used in place of multimode, it can cause signal loss, attenuation, or mismatch between the devices. References: [CompTIA Server+ Certification Exam Objectives], Domain 3.0: Storage, Objective 3.2: Given a scenario, compare and contrast various storage technologies.

Scenario: Migrating a stand-alone application storing PII to the cloud.
Data to Encrypt: Data at rest (Option B) should be encrypted:
Data in transit (Option A) and backups (Option C) are also important but not the primary concern here.
Data archives (Option D) may or may not contain sensitive data.