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
Pin point pupil is seen in A/E : 
Select and explain. 
A. Pontine haemorrhage, B. Organophosphorus poisoning, C. Opium poisoning, D. Barbiturate poisoning
D: Barbiturate poisoning
Answer: D: Barbiturate poisoning 
Explanation: D i.e. Barbiturate All are causes of constricted pupils but in? Barbiturate poisoning the pupils are usually slightly constricted & react to light by alternate contraction & dilation and dilate during terminal asphyxiaQ