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
Diffusion of oxygen at the tissue level is affected in all the following poisonings except: 
Select and explain. 
A. Carbon monoxide, B. Curare, C. Phosgene, D. Cyanides
B: Curare
Answer: B: Curare 
Explanation: B i.e. Curare