Review the detailed description of the study provided below….

Review the detаiled descriptiоn оf the study prоvided below. Which of the following best describes the risk of biаs in this study? Select the one correct one аnswer. The primary outcome of the study was the child’s body mass index (BMI) z-score, calculated using measured height and weight at post-intervention, as pre-specified in the study protocol registered on ClinicalTrials.gov before participant recruitment. The BMI z-score precisely reflects how much a measurement deviates from the mean and is a useful tool for tracking weight changes. A z-score of 0 represents the average BMI for a given age and sex, while a positive z-score indicates a BMI higher than the average for that age and sex group, suggesting potential overweight or obesity. For data collection, parents and children in both the intervention and control groups were invited to participate at baseline and post-intervention. During each data collection session, parents completed an online survey on a study-provided iPad, reporting their child’s nutrition and physical activity behaviors. After the survey, two trained research staff members—who were not involved in delivering the intervention—measured children's height and weight using standardized protocols. Children wore light clothing provided by the study and no shoes during measurements. The trained research staff were not blinded to group assignments. There were no significant differences in measured height or weight between the two measurement staff members.