A prospective cohort study was conducted to determine the risk of heart attack among men with varying levels of baldness. Third-year residents in dermatology conducted visual baldness assessments at the start of the study (which was before any heart attacks had occurred). Four levels of baldness were coded: none, minimal, moderate, and severe. The follow-up rate for this study was 100%. Which of the following types of bias were avoided in this study?(Choose all that apply)a. Recall bias of the exposure information.b. Differential misclassification of the exposure.c. Non-differential misclassification of the exposure.d. Selection bias due to follow up.
