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
Ochronosis is seen in poisoning with 
Select and explain. 
A. Boric acid, B. Carbolic acid, C. Oxalic acid, D. HCl
B: Carbolic acid
Answer: B: Carbolic acid 
Explanation: CARBOLIC ACID (phenol; OH) In the body, phenol is paly oxidised to hydroquinone and pyrocatechol. CHRONIC POISONING (PHENOL MARASMUS) It is characterised by anorexia, weight loss, headache, veigo, dark urine and pigmentation of skin and sclera. The hydroquinone and pyrocatechol may cause pigmentation in the cornea and various cailages, a condition called oochronosis. Oochronosis is commonly associated with alkaptonuria (an inborn error of metabolism), in which homegentisic acid gets deposited in cailages, ligaments and fibrous tissues. Ref:- k s narayan reddy; pg num:-535