Answer:
The correct answer is - All offsprings are black-furred mice.
Explanation:
In this case, the parent mice are black and a cross between these mice produces offspring one allele from both parents. Here, black fur is dominant over white fur.
All the babies are with dark fur colors, no whites as black is a dominant color, so it produces black due to cross between two true breeds.
B B
B BB BB
B BB BB