In a species of mouse, fur colour may be black or white. Two black female mice were each mated with the same black male. One female produced nine offspring, all black. The other female produced seven offspring, of which five were black and two were white. One of the white mice was male and is then allowed to mate with a heterozygous female. What phenotype ratio is expected among their offspring?
- A1 black : 1 white
- B1 black : 3 white
- C1 black : 2 grey : 1 white
- D3 black : 1 white