UKMLA PLAB AMC USMLE Prometric MCQ

Question Number 0031
Question:
A study was performed examining stroke rates when comparing people at work with people on long term sickness leave. Working people were found to have a lower stroke rate. It was concluded that work reduces your risk for stroke. This study most clearly shows

a) recall bias
b) chronologic Bias
c) lead-time bias
d) publication bias
e) selection bias