What Is the Correct Order of Steps of Morphogenesis in Drosophila

Multiple Choice

What is the correct order of steps of morphogenesis in Drosophila melanogaster?
A. Gap genes divide the body into broad regions
B. Establishment of anterior / posterior axes
C. Homeotic genes determine which body parts arise from each region
D. Pair-rule genes are activated in order to develop a preliminary segmentation pattern

A) b - a - d - c
B) a - d - c - b
C) b - a - c - d
D) a - b - c - d
E) a - d - b - c