A floppy disk is best described as which of the following?

A floppy disk is best characterized as a portable magnetic storage medium because it was designed to store data using a magnetic coating on a thin, flexible disk housed within a square or rectangular plastic casing. This allows users to easily transport data between different computers, which is a key feature of portable storage devices. The magnetic nature of the storage allows for data to be written, read, and erased, which is typical of magnetic media.

In terms of the incorrect options, an external hard drive is a more advanced storage solution designed for larger capacities and permanence, typically using magnetic or solid-state technology, and is generally not referred to as a floppy disk. Non-portable tape storage refers to larger data backups and archival systems that do not allow for easy mobility like floppy disks do. Lastly, solid-state storage uses flash memory rather than magnetic media, making it a completely different technology from what is used in floppy disks. Therefore, the identification of a floppy disk as a portable magnetic storage medium accurately reflects its function and technical characteristics.