The pathway above illustrates the role of insulin in the regulation of glucose in the blood. When blood sugar (glucose) levels are elevated, insulin is released to trigger cells to take in glucose. Although insulin never enters the cell, it creates a signaling cascade that mobilizes Glut-4 transporters to the surface of the cell. What describes the movement of glucose into the cell using Glut-4 transporters? A) This is an example of endocytosis. B) This is an example of simple diffusion. C) This is an example of active transport. D) This is an example of facilitated diffusion.