What type of drive stores data on a metal or glass platter coated with a magnetic substance?

The correct choice is the Hard Disk Drive (HDD) because this type of storage device uses a physical disk, typically made from metal or glass, which is coated with a magnetic material. This magnetic coating allows data to be written and read by the drive's read/write heads as they move across the spinning platters. When data is saved to the HDD, it is magnetically encoded onto these platters, allowing for the storage of large amounts of information.

In contrast, a Solid State Drive (SSD) utilizes flash memory chips to store data, which do not involve any moving parts or magnetic coatings. Flash Drives also use flash memory technology, and an External Hard Drive can either be an external enclosure containing an HDD or an SSD, making them not exclusively reliant on the platter-based technology characteristic of HDDs. Thus, the unique structure and function of the HDD make it the appropriate answer to the question regarding storage on a magnetic-coated platter.