A researcher is studying coat color in mice. Wild-type fur in mice is brown. Three pure-breeding strains of mice with white fur have been isolated. The strains are called milky, blanc, and weiss. White fur is a recessive trait in each strain. These mice are crossed to each other in pairs and the progeny phenotypes are recorded: milky × blanc = all brown progeny milky × weiss = all white progeny weiss × blanc = all brown progeny. What conclusion is consistent with these results?
a. all three stains have mutations in the same gene.
b. all three stains have mutations in different gene.
c. the milky and blanc have mutations in the same gene, weiss has a mutation in a different gene.
d. the milky and weiss have mutations in the same gene, blanc has a mutation in a different gene.
e. the weiss and blanc have mutations in the same gene, milky has a mutation in a different gene.