This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Poisoning, Subject name: Forensic Medicine
Parkinsonism like features are evident in surviving patients of which poisoning - 
Select and explain. 
A. CO, B. CO2, C. H2S, D. N2O
A: CO
Answer: A: CO 
Explanation: CO poisoning symptoms- headache CNS-monoplegia,hemiplegia,personality changes,cerebellar damage,parkinsonism bullae CO automatism REF;THE SYNOPSIS OF FORENSIC MEDICINE:KS NARAYANA REDDY;28th EDITION;PAGE NO 359