The first thing that a technician should verify before decommissioning and wiping a file server is non-utilization, which means that no one is using or accessing the server or its data. This can be done by checking logs, monitoring network traffic, or contacting users or stakeholders. Non-utilization ensures that decommissioning and wiping will not cause any data loss or disruption to business operations. Verified References: [Server Decommissioning Checklist]

The administrator should use the command mount -o remount,rw /newdisk to successfully mount the drive with the required parameters. The mount command is used to mount file systems on Linux systems. The -o option specifies options for mounting file systems. The remount option re-mounts an already mounted file system with different options. The rw option mounts a file system with read-write permissions. In this case,
/newdisk is a mount point for a new hard disk that was mounted with read-only permissions by default. To allow users to create directories or files on /newdisk, the administrator needs to re-mount /

The port that must remain open for a secure website is port 443. Port 443 is used by Hypertext Transfer Protocol Secure (HTTPS), which is an extension of HTTP that encrypts and authenticates the communication between a web server and a web browser. HTTPS ensures that the data transmitted over the web is protected from eavesdropping, tampering, or spoofing. Therefore, port 443 must remain open for a secure website to function properly.
References: CompTIA Server+ SK0-005 Certification Study Guide, Chapter 2, Lesson 2.2, Objective 2.2

Explanation
The output of the configuration shows that RAID 5 was configured properly using four 200GB drives. The approximate volume size of 400GB is correct, since RAID 5 uses one disk for parity and the rest for data.
Therefore, the usable storage capacity is three-fourths of the total capacity, which is 600GB out of 800GB.
The other RAID levels given would result in different volume sizes: RAID 0 would result in 800GB, RAID 1 would result in 200GB, and JBOD would result in an error since it does not support multiple drives in a single volume. References: https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_5