This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C. Mycobacteria, Subject name: Skin
How many bacilli should be there in the tissue for slit skin smear to be positive for Hansen's disease? 
Select and explain. 
A. 10 baccili / gram of tissue, B. 102 baccili / gram of tissue, C. 103 baccili i gram of tissue, D. 104 baccili / gram of tissue
D: 104 baccili / gram of tissue
Answer: D: 104 baccili / gram of tissue 
Explanation: Ref: Rook s Textbook of DermatologyExplanation:At least 1114 bacilli should be present per gram tissue for 1+ bacteriological index in slit skin smear,Maximum number of bacilli in a highly bacillated lepromatous leprosy patient is 1012.Average density of bacilli in lepromatous leprosy is 2.5 billion per 1 cm3 tissue.