What does the prefix "an-" signify?

The prefix "an-" is derived from Greek and signifies the absence or lack of something, meaning "without." It is commonly used in medical terminology to describe conditions where a normal element is missing. For instance, in medical terms like "anemia," the prefix indicates a deficiency or lack of blood components. This precise meaning is the reason why "without" is the correct choice.

The other options refer to different concepts: "above" might relate to prefixes like "super-" or "hyper-," "around" could connect to "peri-," and "before" relates to "pre-." These prefixes convey entirely different meanings and are not applicable in this case.