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': "Who has coined and developed the concept 'Theory of web of causation'? \nSelect and explain. \nA. Mc Mohan and Pugh, B. Pettenkoffer, C. John snow, D. Louis Pasteur", 'role': 'user'}, {'content': 'Answer: A \nExplanation: "The web of causation theory was given by MC Mohan and Pugh". It is based upon the epidemiological triad of: Agent Host Environment Ref: Park\'s Textbook of Preventive and Social Medicine, 20 th edition, Page 32.', 'role': 'assistant'}]