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': 'Pseudohemoptysis is caused by: \nSelect and explain. \nA. Histoplasma capsulatum, B. Serratia marcescens, C. Proteus, D. Klebsiella', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Serratia grows\xa0in\xa0sputum after collection and makes sputum red (pigment production) This condition is pseudohemoptysis.', 'role': 'assistant'}]