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
[{'content': 'Gram staining sequence is \nSelect and explain. \nA. Carbol fuchsin – Iodine – Acetone – Methyl violet, B. Methyl violet  –  Iodine – Acetone – Carbol fuchsin, C. Methyl violet – Acetone – Iodine – Carbol fuchsin, D. Carbol fuchsin – Acetone – Iodine – Methyl violet', 'role': 'user'}, {'content': "Answer: B \nExplanation: Primary stain – Crystal violet or Methyl violet\xa0\nMordant – Gram's iodine\nDecolorizer –\xa0Acetone or Ethanol\nSecondary stain –\xa0Safranin or Carbol fuchsin", 'role': 'assistant'}]