In a breed of sheep, coat colour is determined by two independently assorting genes, W/w W/w\,W/w and B/bB/bB/b, which exhibit dominant epistasis. The dominant allele W W\,W suppresses all pigment production, resulting in a white coat. In homozygous recessive ww ww\,ww individuals, the dominant allele B B\,B produces a black coat, whereas the homozygous recessive genotype bb bb\,bb produces a brown coat.
A white sheep with the genotype WwBb WwBb\,WwBb is crossed with another white sheep with the genotype WwbbWwbbWwbb.
What is the expected percentage of offspring from this cross that will have a black coat?
12.5%12.5\%12.5%
25.0%25.0\%25.0%
37.5%37.5\%37.5%
50.0%50.0\%50.0%