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': "E. coli gives pink colour with - \nSelect and explain. \nA. Chocolate agar, B. L.J. medium, C. MacConkey's medium, D. Saline broth", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]