Communication between cells is essential to coordinate the activity of the trillions of cells that make up the human body. Which of the following is/are directly involved in carrying out communication between cells?

A) Lipid bilayer of the plasma membrane
B) Receptor proteins of the plasma membrane
C) Chemical signal molecules released by cells
D) Mitochondria
E) Both "Receptor proteins of the plasma membrane" and "Chemical signal molecules released by cells" are correct.