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: Microbiology
Virulence of mycorbacteria is due to: 
Select and explain. 
A. Mycotoxin production, B. Cell envelope, C. Resistance to inactivation by heat, D. Proteolytic bacteria
B: Cell envelope
Answer: B: Cell envelope 
Explanation: Friends there are multiple factors are listed as virulence factors of the MTC, few of them are:

Lipids and Fatty Acid Metabolism and Synthesis of complex lipids, lipoproteins
Mycolic acid synthesis
Cell envelope and cell wall proteins
Some secretion system
Proteins Inhibiting Antimicrobial Effectors of the Macrophage and protein kinases
Different Proteases and proteins associated with it
Apoptosis inhibition and arresting the phagosome