What does rust refer to in rabbit coloration?

Rust refers to a specific fur coloration in rabbits characterized by a reddish-brown hue. This descriptor relates to the visual appearance of the fur, typically having warm, earthy tones reminiscent of rusted metal, which is where the term derives its name. In various rabbit breeds, this coloration can be featured prominently in their coat patterns, contributing to their overall aesthetic and breed standards.

Understanding the term 'rust' in this context is essential for recognizing color variations in rabbits, especially in show settings or breeding discussions. The other options do not align with the correct definition of rust in rabbit coloration, as they either misrepresent the color or refer to unrelated concepts.