This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Systemic Bacteriology (Gram Positive Bacilli, Gram Negative Bacilli), Subject name: Microbiology
[{'content': 'The factor which promotes virulence of M.tuberculosis - \nSelect and explain. \nA. Wax D, B. Cord factor, C. Muramyl dipeptide, D. Mycolic acid', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Factors responsible for virulence of Mycobacterium tuberculosis- * Cord factor Lipo arabino mannose Heat shock protein', 'role': 'assistant'}]