Answer:
White: A---
Black: aaB-
Brown: aabb
Explanation:
As per given information, the genotype of parent white sheep is AaBb (heterozygous white).
The gene "A" is dominant over gene "B". Hence, all the genotypes with one or two copies of "A" would exhibit white phenotype.
All the genotypes that have "aa" and one or two "B" alleles would exhibit black phenotype.
All the genotypes with "aabb" allele combination would exhibit brown phenotype.