This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Bacteria, Subject name: Microbiology
[{'content': "Nocardia is stained by: \nSelect and explain. \nA. Acid fast stain, B. Kiram's stain, C. Alcian blue, D. Mucin stain", 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Acid fast stainRef:(Ananthanarayan, 8th/e, p. 393; 9th/e, p. 390-91)The first step in diagnosis is examination of sputum or pus for crooked, branching, beaded, gram-positive filaments 1 um wide and up to 50 um long. Most nocardiae are acid-fast in direct smears if a weak acid is used for decolorization (e.g., in the modified Kinyoun, Ziehl-Neelsen, and Fite-Faraco methods). The organisms often take up silver stains.", 'role': 'assistant'}]