QSFP+ is a type of connector that should be used to connect a server to a switch that uses 40G network connectivity. QSFP+ (Quad Small Form-factor Pluggable Plus) is a compact, hot-pluggable transceiver module that supports data rates up to 40 Gbps. QSFP+ modules can be used for various network protocols and media types, such as Ethernet, Fibre Channel, InfiniBand, or optical fiber. QSFP+ modules have a 38-pin edge connector and can be inserted into a QSFP+ port on a switch or a server. SFP+ (Small Form-factor Pluggable Plus) is a type of connector that supports data rates up to 10 Gbps, but not 40 Gbps. SFP+ modules have a
20-pin edge connector and can be inserted into an SFP+ port on a switch or a server. GBIC (Gigabit Interface Converter) is an older type of connector that supports data rates up to 1 Gbps, but not 40 Gbps. GBIC modules have an SC duplex connector and can be inserted into a GBIC port on a switch or a server. SFP (Small Form-factor Pluggable) is another older type of connector that supports data rates up to 1 Gbps or 4 Gbps, but not 40 Gbps. SFP modules have an LC duplex connector and can be inserted into an SFP port on a switch or a server. References:
https://www.howtogeek.com/190014/virtualization-basics-understanding-techniques-and-fundamentals/
https://www.howtogeek.com/428483/what-is-end-to-end-encryption-and-why-does-it-matter/
https://www.howtogeek.com/443611/how-to-encrypt-your-macs-system-drive-removable-devices-and-individua

RAID 6 is a RAID level that uses disk striping with two parity blocks distributed across all member disks. It can tolerate the failure of up to two disks without losing any dat a. RAID 6 can provide a minimum of 10TB of usable storage space with five 4TB disks, as the formula for calculating the RAID 6 capacity is (n-2) x Smin, where n is the number of disks and Smin is the smallest disk size. In this case, the RAID 6 capacity is (5-2) x 4TB = 12TB.
References:
CompTIA Server+ Certification Exam Objectives1, page 8
RAID Levels and Types Explained: Advantages and Disadvantages2
RAID Levels & Fault Tolerance3

A differential backup is a type of backup that copies all the files that have changed since the last full backup. A differential backup requires more storage space than an incremental backup, which only copies the files that have changed since the last backup of any type, but it also requires less time to restore in case of data loss. By combining a full, weekly backup with daily differential backups, the administrator can ensure that only two backup sets are needed to restore a full backup as quickly as possible. Verified Reference: [Incremental vs Differential Backup]

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