This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
Identification of cholera by Snow is an example of? 
Select and explain. 
A. Spot map, B. Random trial, C. Analytical design, D. Experimental design
A: Spot map
Answer: A: Spot map 
Explanation: <p> John Snow of England in his classic investigation of cholera epidemic in 1854 is an example of spot map. Park&;s textbook of preventive and social medicine,K.Park,23rd edition,page no:66 <\p>