For most computers, the largest storage device is the hard drive or SSD. ... For example, over the evolution of the hard drive, their storage capacity has increased from 5 MB to several terabytes in size.
So, the correct answer is hard disk that is " B "

The largest data storage device in a computer is the hard disk.
The hard disk is a non-volatile storage device that is used to store and retrieve digital information. It is typically the largest storage device in a computer and is responsible for holding the operating system, software applications, and user data. Here are some key points to consider:
- Capacity: Hard disks have significantly higher storage capacities compared to other storage devices. They are available in various sizes, ranging from a few hundred gigabytes (GB) to several terabytes (TB) of storage space.
- Physical Structure: A hard disk consists of one or more spinning disks, known as platters, which are coated with a magnetic material. The platters are mounted on a spindle and rotate at high speeds. Data is stored on these platters in the form of magnetic patterns.
- Read and Write Operations: The hard disk uses read/write heads to access and modify data on the spinning platters. The heads move across the platters to read or write data by detecting the magnetic patterns.
- Speed: Hard disks have relatively slower access and data transfer speeds compared to other storage devices, such as solid-state drives (SSDs). This is because the read/write heads need to physically move to the correct location on the platters.
- Permanent Storage: Unlike volatile memory (RAM), the data stored on a hard disk is retained even when the computer is powered off. This makes it a suitable choice for long-term storage of files and applications.
- External Hard Drives: In addition to internal hard disks, there are also external hard drives that can be connected to a computer via USB or other interfaces. These provide additional storage space and can be easily transported.
In conclusion, the hard disk is the largest data storage device in a computer. It offers high storage capacity, permanent storage, and is responsible for holding the operating system and user data.