This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacterial infections, Subject name: Dental
[{'content': 'Grenz zone is absent in which type of leprosy \nSelect and explain. \nA. TT, B. BT, C. BB, D. LL', 'role': 'user'}, {'content': 'Answer: A \nExplanation: LEPROSY:- Ref:- Review of Dermatology by Alikhan; pg num:-303', 'role': 'assistant'}]