Answer:
C. Glucose and oxygen.
Explanation:
The blood-brain barrier is a composition of endothelial cells that regulate the entry of substances into the extracellular fluid found in the central nervous system. Their high degree of selective permeability ensures that no solutes can cross the barrier, and only the right substances which are crucial to the workings of the central nervous system can scale through.
Oxygen which is needed for the proper functioning of the central nervous system and which is hydrophobic in nature is allowed to pass the blood-brain barrier. Glucose too which is an important nutrient/macromolecule for brain health can also move through the blood-brain barrier.
