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: Pharmacology
Drug containing two sulfhydryl groups in a molecule? 
Select and explain. 
A. BAL, B. EDTA, C. Pencillamine, D. None of the above
A: BAL
Answer: A: BAL 
Explanation: Ans. is 'a' i.e., BAL o Dimercaprol (British Anti-Lewisite, BAL) contains two sulfahydryl groups. Note - Penicillamine has one SH group.