Which of the following is a secondary memory device?

A floppy diskette is a secondary storage device that keeps data outside main memory.

The CPU is the processing unit, not a storage device.

The ALU performs arithmetic and logic inside the processor, storing nothing permanently.

Since a valid device is listed, none of the above does not apply.

Secondary storage retains data even after the power is off.

Floppy disks were once common but are now largely obsolete.