This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Toxicology - 2, Subject name: Forensic Medicine
Which of the chemical is used in forgery for removing ink? 
Select and explain. 
A. Oxalic acid, B. Acetic acid, C. Formic acid, D. Ammonia
A: Oxalic acid
Answer: A: Oxalic acid 
Explanation: Oxalic acid is used in cleaning iron rust, bleaching & dyeing. Ink remover solutionQin cases of forgery.