Drosophila Mutations Such as Bcd, If Homozygous in the Mother

Multiple Choice

Drosophila mutations such as bcd, if homozygous in the mother, produce offspring with lethal defects, no matter what the genotype of the offspring. For some other genes, the mutant phenotype can be "rescued" by introducing a wild-type allele. What is the reason for these different outcomes?

A) Non-rescuable mutations are of paternal origin.
B) Rescuable mutations act as dominants.
C) bcd is a maternal effect mutation.
D) Rescue requires recombination between the maternal and introduced alleles.
E) bcd is a Hox gene.