Which is the most accurate description of the usefulness of cache memory?

Correct answer: It keeps frequently used data close to the central processing unit

The governing concept is locality of reference. Programs often reuse the same instructions or data, so cache keeps frequently accessed information in a small, fast memory near the CPU. When the needed item is found there, access takes less time than retrieving it from main memory. Therefore option D is correct. Cache is not a permanent backup, printer controller or printing device, as the other options suggest.