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': 'Selective agent for Mycobacteria in LJ medium is : \nSelect and explain. \nA. Methylene blue, B. Malachite green, C. Mineral salt solution, D. Glycerol', 'role': 'user'}, {'content': 'Answer: B \nExplanation: LJ medium contains- ? Potassium dihydrogen phosphate anhydrous , Magnesium sulphate anhydrous, Magnesium citrate ? Asparagine and Glycerol ? Malachite green, 2% solution ? Eggs', 'role': 'assistant'}]