K gene in mice is known to be paternally imprinted (paternal copies are silenced) and expressed during embryogenesis.

K gene in mice is known to be paternally imprinted (paternal copies are silenced) and expressed during embryogenesis. A mutation occurred on the promoter of K gene and this promoter lost its ability to bind to RNA polymerase. A female mouse is heterozygous for this mutant allele and the wild-type allele of K gene. If this female produces embryos by mating with a male, which is also heterozygous at this locus, what proportions of male and female embryos will express K protein? Why?