Which type of memory is referred to as non-volatile?

Non-volatile memory is a type of storage that retains data even when the power is turned off. This characteristic is crucial for data preservation and is what distinguishes non-volatile memory from volatile memory, which requires a continuous power supply to maintain the stored information.

In this context, the option that states "memory that retains data without power" directly describes the essence of non-volatile memory. Examples of non-volatile memory include flash memory, hard drives, and SSDs, which can store data permanently, unlike volatile types such as RAM, which lose their contents when power is lost.

Other options, like dynamic RAM and synchronous RAM, both fall under the category of volatile memory. They require continuous power supply to retain data, thus do not meet the criteria of non-volatile memory. Cache memory, while it serves as a faster storage for CPUs, also loses information when powered down, making it a form of volatile memory as well.

Therefore, the option regarding memory that retains data without power accurately captures the defining feature of non-volatile memory.