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
Main purpose of Randomisation is 
Select and explain. 
A. To eliminate selection Bias, B. To remove confounding factor, C. For good results, D. To eliminate Analysis Bias
A: To eliminate selection Bias
Answer: A: To eliminate selection Bias 
Explanation: None