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: Forensic Medicine
Which is a spinal poison: 
Select and explain. 
A. Strychnine, B. Organophosphorus, C. Oleander, D. Cannabis
A: Strychnine
Answer: A: Strychnine 
Explanation: Strychnine