The Sex of Birds, Some Insects, and Other Organisms Is

The sex of birds, some insects, and other organisms is determined by a ZW chromosomal arrangement in which the males have like sex chromosomes (ZZ) and females are ZW (similar to XY in humans) . Assume that a recessive lethal allele on the Z chromosome causes death of an embryo in birds. What sex ratio would result in the offspring if a cross were made between a male heterozygous for the lethal allele and a normal female?

A) 1:2 male to female
B) 4:1 male to female
C) 1:1 male to female
D) 2:1 male to female
E) 3:1 male to female