This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Confounding and Bias, Subject name: Social & Preventive Medicine
All of the following are investigator bias except:- 
Select and explain. 
A. Interviewer bias, B. Misclassification bias, C. Hawthorne bias, D. Pygmalion bias
C: Hawthorne bias
Answer: C: Hawthorne bias 
Explanation: Bias:- Type of Systemic Error in Study; Subject Bias (Eg : Recall Bias, Hawthorne bias) Investigator Bias (Interviewer Bias, Misclassification Bias, Selection Bias) Analyzer Bias (calculation error)