All cells in a multicellular organism have normally developed from a single cell and share the same genome, but can nevertheless be wildly different in their shape and function. What in the eukaryotic genome is responsible for this cell-type diversity?

A) The genes that encode transcription regulatory proteins
B) The regulatory sequences that control the expression of genes
C) The genes that code for molecules involved in receiving cellular signals
D) The genes that code for molecules involved in sending cellular signals to other cells
E) All of the above