Which of the Following Statements About Differentiated Cells Is TRUE

Which of the following statements about differentiated cells is TRUE?

A) Cells of distinct types express nonoverlapping sets of transcription regulators.
B) Once a cell has differentiated, it can no longer change its gene expression.
C) Once a cell has differentiated, it will no longer need to transcribe RNA.
D) Some of the proteins found in differentiated cells are found in all cells of a multicellular organism.