This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tuberculosis, Subject name: Social & Preventive Medicine
[{'content': 'BCG is a? \nSelect and explain. \nA. Immunomodulator, B. Live attenuated vaccine, C. Killed vaccine, D. Toxiod vaccine', 'role': 'user'}, {'content': "Answer: B \nExplanation: ANSWER: (B) Live attenuated vaccineREF: APPENDIX-46 below TYPES OF VACCINE & IMMUNIZATIONRepeat Community medicine 2012 Session 1, 2008, Pediatrics June 2009 APPENDIX - 46Types of VaccineTypeContentExamplesKilled vaccineskilled, but previously virulent, microorganisms that have been destroyed with chemicals or heat.Avian Flu vaccine; developed by Reverse Genetics techniques. Reverse genetics' is an approach to discovering the function of a gene by analyzing the phenotypic effects of specific gene sequences obtained by DNA sequencing. This investigative process proceeds in the opposite direction of so- called forward genetic screens of classical genetics. Simply put, while forward genetics seeks to find the genetic basis of a phenotype or trait, reverse genetics seeks to find what phenotypes arise as a result of particular genes.", 'role': 'assistant'}]