What is the rarest color of banana?

I'm intrigued by the concept of a rare color of banana. Typically, we associate bananas with their signature yellow hue, but is it possible that there exists a more elusive color variation? Could you elaborate on what might constitute the rarest color of banana, and perhaps provide some insight into the science behind its rarity? Are there any specific environmental or genetic factors that contribute to the development of this unusual hue?