A group of investigators in Singapore completed a major prospective cohort study to examine the association between air pollution exposure and onset of asthma. Over the course of the 6 10-year follow-up, there was 10% loss to follow-up. The investigators compared data on the exposure status for participants who remained in the study with those who were lost to follow- up. By doing so, the investigators observed that the rate of loss to follow-up did not differ between the exposed and unexposed groups. Based on this information, which one of the following statements is most likely to be true? 12 election bias did not occur in this study because exposure status did not influence whether or not people dropped out of the study (in other words, there was no difference 15 V in loss to follow-up between exposure arms) Selection bias did not occur in this study because people cannot choose if they are 18 exposed to air pollution or not exposed to air pollution V Selection bias occurred in this study because both of the outcome groups (people with 21 asthma and people without asthma) experienced loss to follow-up Selection bias occurred in this study because both the exposed and unexposed groups experienced equal amounts of loss to follow-up