Female Drosophila That Are Homozygous for the Bicoid Maternal Effect

Female Drosophila that are homozygous for the bicoid maternal effect gene mutation produce larvae with no head or thorax. When cytoplasm from the anterior end of a wild-type egg is inoculated into the anterior end of a bicoid mutant egg, the treated egg develops normally. What causes the restoration of normal development in the mutant eggs?

A) Disruption of mutant bicoid gene expression after their inoculation with wild-type egg cytoplasm
B) Normal bicoid gene expression
C) Expression of the nanos gene
D) Induction of normal development by adjacent embryo cells
E) The inoculation of normal egg cytoplasm