Answer:
6
Step-by-step explanation:
In this scenario, black fur (F) is dominant to white fur (f) and black eyes (E) are dominant to red eyes (e). So in this case you would be looking for all lowercase letters in the punnet square, which would only be 1 mouse with white fur and red eyes (ff ee), and since there are 16 potential genotypes for offspring and only 1 that would be white with red eyes, you would divide 1 by 16 and get 0.0625, then you would multiply 0.0625 by 100 (total number of mice) and you would get 6.25. since you can't really have .25 of a mouse (that would be kind of gross) you round down and get 6, the closest answer.
(Also I just took this quiz and got this question right. Just wanted to confirm that in case you had any doubts!)
Hope this helped!