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: Medicine
Drug used to halt process of degeneration of dopaminegric neurons in nigrostrial pathway is - 
Select and explain. 
A. Vit E, B. Vit A, C. Propranolol, D. Levodopa
A: Vit E
Answer: A: Vit E 
Explanation: None