This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
A patient present to emergency with pinpoint Pupil,salivation, lacrimation, tremors and red tears. Plasma chlolinesterase level was 30% of normal. Most probable diagnosis is 
Select and explain. 
A. Organophosphate poisoning, B. Datura poisoning, C. Opioid poisoning, D. Pontine hemorrhage
A: Organophosphate poisoning
Answer: A: Organophosphate poisoning 
Explanation: These are characteristic features of anti-cholinestearse(organophosphate and carbamate) poisoning. Features of Organophosphate poisoning: Muscarinic symptoms: Pin point pupil, salivation,lacrimation, urination, defecation, gastrointestinal distress, vomiting, bronchospasm, bradycardia Nicotinic symptoms: Fasciculations and fibrillations of muscle, tachycardia, tachypnea CNS symptoms: Temors, giddiness, ataxia, coma Red tears: Due to accumulation of porphyrin in the lacrimal glands Ref-Katzung 12/e p110