In a prospective cohort study ofasthma and breastfeeding, the incidence of asthma (after adjusting for parental smoking) inbreastfed children was 5 per 1000 and 10 per 1000 in those not breastfed. In the same study, parents of children not breastfed were more likely to smoke than parents of breastfed children. The inference that breastfeeding protectsagainst asthma based on this studyis most likely to be: (assume no other competing risk or preventive factors)

A.Correct

B.Incorrect because cross-sectional studies are not appropriate to determine risk of disease

C.Incorrect because rates and not proportions were used to compare males and females

D.Incorrect because there is no comparison or control group

E.Might be correct but we need to account for the effect of parental smoking to obtain a more valid answer