Password length is the first password policy that the administrator should implement to help mitigate the chance of a successful brute-force attack. A brute-force attack is a method of guessing passwords by trying all possible combinations of characters until the correct one is found. The longer the password, the more combinations there are, and the more time and resources it takes to crack it. Therefore, password length is a key factor in password strength and security.
References: CompTIA Server+ SK0-005 Certification Study Guide, Chapter 3, Lesson 3.2, Objective 3.2

The best solutions to resolve the concern of transmissions from the building being detected from outside are signal blocking and reflective glass. Signal blocking is a method of preventing or interfering with electromagnetic signals from escaping or entering a certain area. Signal blocking can be achieved by using various materials or devices that create physical barriers or generate noise or jamming signals. Signal blocking can protect data transmissions from being intercepted or eavesdropped by unauthorized parties. Reflective glass is a type of glass that has a coating or film that reflects light and heat. Reflective glass can reduce glare and solar radiation, as well as prevent visual observation from outside. Reflective glass can enhance privacy and security for datacenter operations.

A rescan on the server's RAID controller is a possible troubleshooting step to detect the existing RAID configurations on the connected storage arrays. A firmware upgrade may cause the RAID controller to lose the RAID metadata or settings, and a rescan may restore them. A rescan is preferable to restoring the default RAID configuration, as the latter may erase the existing data on the arrays. Power cycling the storage arrays or booting the OS into recovery mode may not help if the RAID controller does not recognize the RAID sets.
References: CompTIA Server+ Study Guide, Chapter 7: Storage, page 287.

User activity reports were used to identify the security breach in the human resources department. User activity reports are records of the actions and events performed by users on a system or network, such as login/logout times, files accessed or modified, commands executed, or websites visited. User activity reports can help monitor and audit user behavior, detect and investigate security incidents, and enforce policies and compliance. User activity reports can be generated by various tools, such as log management software, security information and event management (SIEM) systems, or user and entity behavior analytics (UEBA) solutions. References: [CompTIA Server+ Certification Exam Objectives], Domain 5.0: Security, Objective 5.2: Given a scenario, apply logical access control methods.