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: Unknown
[{'content': 'Theory of the web of causation was given by? \nSelect and explain. \nA. Mc Mohan and Pugh, B. Pettenkoffer, C. John snow, D. Louis Pasteur', 'role': 'user'}, {'content': 'Answer: A \nExplanation: ANSWER: (A) Mc Mohan and Pugh REF: Park 20th edition page 32 Repeat from December 2010 "The web of causation theory was given by MC Mohan and Pugh" It is based upon the epidemiological triad of: Agent Host Environment', 'role': 'assistant'}]