This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Social & Preventive Medicine
True about confounding factor -a) It is found equally between study and the control groupsb) It is itself a risk factor for the diseasec) Confounding can be eliminated by selecting a small groupd) It is associated with etiher the exposure or the disease 
Select and explain. 
A. ac, B. ab, C. abc, D. c
B: ab
Answer: B: ab 
Explanation: None