What is a primary characteristic of a hard disk drive (HDD)?

The primary characteristic of a hard disk drive (HDD) is its use of magnetic sections to read and write data. HDDs store data on rotating platters coated with a magnetic material. An actuator moves a read/write head across the disk surfaces to access or modify the data by aligning the magnetic fields within these sections. This technology relies on the physical movement of these parts, which is fundamental to the operation of HDDs.

The other choices don't accurately describe HDDs. For example, while it is true that some modern storage solutions, like solid-state drives (SSDs), have no moving parts, HDDs are characterized by their mechanical components. Additionally, HDDs are generally considered to be less expensive compared to flash drives, particularly for larger capacities, which contradicts the idea that they are significantly more expensive. Lastly, HDDs typically consume more energy than flash drives due to their moving parts and mechanical operations, rather than requiring less energy.