Answer:
D: The trait of agouti fur is dominant over the trait of black fur.
Step-by-step explanation:
A is not true because you can clearly see that there is a chance for the offspring to have black fur.
B is false because there is a 50% chance for the offspring to have agouti fur and 50% for black fur. If the trend keeps going, not all the mice would end up with black fur.
C can't be the answer because that just makes no sense. If you don't like my reasoning, neither do I. It just doesn't feel right.