This Graph Shows the Normal Concentration of Morphogens a and B

This graph shows the normal concentration of morphogens A and B throughout a Drosophila embryo.
If morphogen B is injected into the head end of an embryo, the embryo is likely to develop

A) normally.
B) a second tail at the head end
C) a second head at the tail end.
D) two heads at the head end.