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
Randomization is useful to eliminate 
Select and explain. 
A. Observer bias, B. Confounding factors, C. Patient bias, D. Sampling bias
B: Confounding factors
Answer: B: Confounding factors 
Explanation: Randomization: The groups should be alike with regard to ceain variables or characteristics that might affect the outcome of experiments The entire study population can be stratified into subgroups according to the variable Individuals within each subgroup can then be randomly allocated into study and control groups Ref: 25th edition, Park's Textbook of Preventive and Social Medicine, Page no. 90