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
Study unit Ecological study is:- 
Select and explain. 
A. Population, B. Patient, C. Community, D. Case
A: Population
Answer: A: Population 
Explanation: 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