Which storage type is primarily used for long-term data retention in a computer?

The correct answer is Solid State Drive. This type of storage is designed specifically for long-term data retention and is known for its durability and speed compared to traditional hard drives. Solid State Drives (SSDs) retain data even when the computer is powered off, making them ideal for storing operating systems, applications, files, and other critical data that need to be preserved.

In contrast, RAM (Random Access Memory) is volatile memory, meaning it loses its data when the computer is turned off. Cache memory, which is used for temporarily holding frequently accessed data for fast retrieval, also does not retain information when powered down. CPU registers are small storage locations within the CPU itself, used for quick access by the processor while executing instructions. They also do not provide long-term storage for data. Therefore, for the purpose of long-term data retention, Solid State Drives are clearly the appropriate choice.