Explanation
Drive encryption is a form of encryption that best achieves the goal of data-at-rest encryption for all data.
Drive encryption encrypts the entire hard drive, including the operating system, applications, and files. This prevents unauthorized access to the data if the drive is lost or stolen. Database, folder, and file encryption are forms of encryption that only encrypt specific data sets, not all data. References: [CompTIA Server+ Certification Exam Objectives], Domain 5.0: Security, Objective 5.3: Given a scenario involving a security threat/vulnerability/risk, implement appropriate mitigation techniques.

To disable root login over SSH, the server administrator needs to edit the SSH configuration file located at
/etc/ssh/sshd_config. This file contains various settings for the SSH daemon that runs on the server and accepts incoming SSH connections. The administrator needs to find the line that says PermitRootLogin and change it to no or comment it out with a # symbol. Then, the administrator needs to restart the SSH service for the changes to take effect. References:
https://www.howtogeek.com/828538/how-and-why-to-disable-root-login-over-ssh-on-linux/

A crash cart is the best low-cost option to connect to any server while on site in a data center with multiple server racks. A crash cart is a mobile unit that contains a monitor, a keyboard, a mouse, and cables that can be plugged into any server for direct access and control. A crash cart can be used for troubleshooting, maintenance, or configuration of servers without requiring remote access or network connectivity. A crash cart is also easy to move around and store in a data center. Reference: [CompTIA Server+ Certification Exam Objectives], Domain 2.0: Hardware, Objective 2.4: Given a scenario involving server management issues (e.g., remote access), troubleshoot using appropriate tools.