What characteristic describes a rabbit considered "racy"?

A rabbit described as "racy" is characterized by its slender body and active demeanor. This term typically refers to breeds that are built for agility and speed, as opposed to those that are stocky or heavy. Rabbits with a racy build tend to have longer limbs, a leaner physique, and an enthusiastic, energetic personality. These traits make them well-suited for quick movements and active behaviors, which is often desirable in competitive settings or certain types of rabbit exhibitions.

The other options represent traits associated with different body types. For example, a short and stocky build refers more to compact or heavy-set breeds that are not considered racy. Long ears and a fluffy tail relate to aesthetic and physical features that can be found in various rabbit breeds but do not define a racy rabbit. Large size and heavy fur would align more with breeds that are meant for different purposes, such as meat production or as fur animals, rather than active performance or agility. Thus, the description of a racy rabbit aligns best with a slender body and an active demeanor, making that the most accurate choice.