This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: NEET 2018, Subject name: Social & Preventive Medicine
[{'content': 'Study unit Ecological study is:- \nSelect and explain. \nA. Population, B. Patient, C. Community, D. Case', 'role': 'user'}, {'content': 'Answer: A \nExplanation: STUDY TYPE UNIT OF STUDY Coho Individual Case Control Individual Cross Sectional Individual Ecological Population RCT Patient/Case Descriptive Population Since the unit of Ecological study is population, results cannot be applied at individual level.This is known as ECOLOGICAL FALLACY', 'role': 'assistant'}]