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
Bias can be eliminated by all except- 
Select and explain. 
A. Matching, B. Blinding, C. Randomization, D. Multivariate analysis
D: Multivariate analysis
Answer: D: Multivariate analysis 
Explanation: Bias may arise due to errors of assessment of the outcome due to the human element. 3 sources: subject variation, observer bias, bias in evaluation. Selection bias: cases and controls may not be representative of cases and controls in population. There may be a systemic difference in characteristic between cases and controls. (refer pgno:83 park 23 rd edition)