What is meant by 'luster' in rabbit fur?

Luster in rabbit fur refers specifically to the brightness or brilliance of the fur. It is an important characteristic that can indicate the health and quality of the rabbit's coat. A high luster typically suggests that the fur is well-maintained and reflects light effectively, enhancing its overall appearance. This quality is particularly important in competitions and shows, as judges often evaluate a rabbit's fur based on its luster among other attributes.

The other choices focus on different characteristics of the fur that do not pertain to its luster. The smell relates to hygiene and cleanliness, thickness addresses the density and warmth of the coat, and softness pertains to how the fur feels to the touch. None of these aspects capture the visual appeal and reflective quality that luster signifies in rabbit fur.