Theory of web of causation was given by: (A) Mc Mohan and Pugh, (B) Petfenkoffer, (C) John snow, (D) Louis Pasteur
Answer is A. Theory of web of causation was proposed by MacMahon and Pugh in their book: "Epidemiological Principles and Methods". Web of causation considers all the predisposing factors of any type and their complex inter-relationship with each other. Ref : Park&;s Textbook of Preventive and Social Medicine; 23rd edition; Page 34