Which of the following refers to a portable plug-n-play device used as a backup storage device?

The correct choice is the external hard drive, which is a portable storage device that connects to a computer using a USB or other interface and is specifically designed for backup purposes. External hard drives offer significant storage capacity, often far greater than flash drives, and provide reliable data redundancy, making them ideal for backing up important files and data. They are generally easy to use, as they can be plugged into a computer without requiring any additional installation, hence the term "plug-n-play."

An external hard drive is particularly useful for backing up large amounts of data due to its high capacity and typically faster read/write speeds compared to other portable storage options. This versatility makes it a preferred choice for users who need a reliable solution for extending their storage or backing up critical information.

In contrast, other options have characteristics that do not align with being described as a backup storage device. A flash drive, while portable and useful for transferring smaller files, typically has a smaller storage capacity compared to external hard drives. An optical disc, such as CDs or DVDs, is not as flexible for quick backups and has a limited lifespan and durability compared to external hard drives. Lastly, a network drive is more complex as it involves a network connection and is generally used for storage solution scenarios that require