The substance that aids in the transport of glucose from outside of the cell to inside of the cell are the protein. The answer is letter C. There is a thing called channel protein that allows the transport of specific substance across the cell membrane.
Glucose pass through cell membrane via specific protein transporters which aid in moving compounds in/out of the cell. Facilitated diffusion occurs at the expense of ATPs, beacuse glucose is too big to be transported via simple diffusion.
