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 which causes hypothyroidism is ? 
Select and explain. 
A. Carbamezapine, B. Lithium, C. Sulphur, D. Methotrexate
B: Lithium
Answer: B: Lithium 
Explanation: Ans. is 'b' i.e., Lithium