Studies Have Shown That in the Flowering Plant Arabidopsis the Root-Shoot

Studies have shown that in the flowering plant Arabidopsis the root-shoot axis is established ____.

A) by the first cell division of the embryo
B) within hours after the seed germinates
C) during the torpedo stage of embryonic development
D) shortly after the eight-cell embryo stage
E) by plant tissues breaking through the seed coat and making contact with soil