Who has a funny joke for his girlfriend?

Little white rabbit's sister got lost at the fork in the road, met little gray rabbit and asked, "Brother Grey, do you know where our home is?" Little grey rabbit looked around, but there was no one there. No, there are no rabbits around. She has bad ideas. "Do you want to know?" "think!" "Then you have to make me happy!" The white rabbit makes him very happy. He said, "Turn left." (unfinished ...) so the little white rabbit left. Soon, he met the little black rabbit at the fork in the road. "Brother Hei, do you know where our home is?" The little black rabbit looked around and didn't see the rabbit. His heart was full of evil thoughts. "Do you want to know?" "think!" "Then you have to make me happy!" So the white rabbit made him very happy. He said, "To the left." The little white rabbit continued to walk. When he came home, he gave birth to a litter of long-haired rabbits.

So, what color is the rabbit's hair? The girl who listened to the story said, "White!" "no!" "The gray one?" "Not really!" "Black?" "Not yet!" "What color is that?" "Do you want to know?" "think!" "Really?" "Yes!" "Then you have to make me happy ~"