This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
Which of the following does not cross blood brain barrier ? 
Select and explain. 
A. Glycopyrolate, B. Atropine, C. Scopolamine, D. Promethazine
A: Glycopyrolate
Answer: A: Glycopyrolate 
Explanation: None