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
The factor which promotes virulence of M.tuberculosis - 
Select and explain. 
A. Wax D, B. Cord factor, C. Muramyl dipeptide, D. Mycolic acid
B: Cord factor
Answer: B: Cord factor 
Explanation: Factors responsible for virulence of Mycobacterium tuberculosis- * Cord factor Lipo arabino mannose Heat shock protein