Which Statement About Gene Cascades Is False

Which statement about gene cascades is false?

A) Gene cascades control simple but not complex behavioral phenotypes.
B) Certain genes within cascades influence many other genes.
C) The fru gene is part of the gene cascade that controls male courtship behavior in fruit flies.
D) A gene cascade controls sexual differentiation in fruit flies.
E) Changes in a single gene within a gene cascade can affect an animal's behavior and ultimately its fitness.