Answer:
The correct answer is option - C amino acids.
Step-by-step explanation:
The blood brain barrier or BBB is border that separates extracellular fluid in the central nervous system (CNS) and the blood that is circulating from the brain.
This barrier is allows the passage by facilitate diffusion (passive diffusion) and through the selective proteins of molecules such as glucose, amino acids that are essential for the neural function.
Thus, the correct answer is - amino acids.