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
In a case controlled study. It is found that the disease is more common in the group taking coffee as compared to the control group. The significance of this is- 
Select and explain. 
A. Cause and effect relationship established, B. Disease median can be calculated, C. Caffeine is associated with occurrence of disease, D. Controls will not get the disease
C: Caffeine is associated with occurrence of disease
Answer: C: Caffeine is associated with occurrence of disease 
Explanation: Case-control studies basically comparison study. Cases and control must be comparable with respect to known "confounding factor "such as age , sex occupation, social status, etc. The questions asked relate to personal characteristics and antecedent exposures which may be responsible for the condition studied.