What kind of bias is present in 2b? In a sentence or two, please indicate the observed and true ORs, and they type and direction of the bias present in 2a-2c. What would the observed OR of age at menarche and ovarian cancer be if 90% of cases and 80% of controls who were actually younger than 12 at menarche reported their age at menarche accurately? Please describe the results of 2e in a sentence including the type and direction of the bias present, and how it compares with your results in 2b