This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Epidemiology, Subject name: Social & Preventive Medicine
Case control study method has following three distinct features. Select inappropriate one 
Select and explain. 
A. Both exposure and outcome have occurred before the sta of the study, B. Unit of study is group rather than individual, C. The study proceeds backward from effect to cause, D. It uses a control or comparison group to suppo or refute an interference
B: Unit of study is group rather than individual
Answer: B: Unit of study is group rather than individual 
Explanation: Case control Study - Case control studies, often called as"retrospective studies" .It has 3 distinctive features both exposure and outcome (disease) have occurred before the sta of the study. the study proceeds backwards from effect to cause. it uses a control or comparison group to suppo or refute an inference. - In case control studies,the unit is individual rather than the group. EXTRA EDGE: UNIT OF STUDY: Coho study, Case control study, Cross sectional study - Individual Ecological study, Descriptive study - Population.