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
A patient with suspected poisoning has brownish oral mucosa and tongue, constricted pupil and greenish brown urine, poisoning is with - 
Select and explain. 
A. Carbolic acid, B. Morphine, C. H2SO4, D. Cannabis
A: Carbolic acid
Answer: A: Carbolic acid 
Explanation: Brownish oral mucosa and tongue (due to corrosion), constricted pupil and greenish brown urine is seen in carbolic acid (phenol) poisoning.