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
Preference of epidemiological studies for establishing causality:- 
Select and explain. 
A. RCT > Retrospective coho > Prospective coho > Case control > Cross sectional, B. RCT > Prospective coho > Retrospective coho > Case control > Cross sectional, C. RCT > Prospective coho >Retrospective coho > Cross sectional > Case control, D. RCT > Retrospective coho > Prospective coho > Cross sectional > Case control
A: RCT > Retrospective coho > Prospective coho > Case control > Cross sectional
Answer: A: RCT > Retrospective coho > Prospective coho > Case control > Cross sectional 
Explanation: Preference of epidemiological studies for establishing causality:- Double blind RCT > Retrospective coho > Prospective coho > Case control > cross sectional > Ecological study.