"An investigator was interested in the etiology of neonatal jaundice. To study the causes of the condition she selected 1,000 pregnant women and interviewed them immediately after their pregnancy was first detected. The women were then followed up and monitored carefully during their pregnancy to detect exposure to possible causes of neonatal jaundice. Their babies were examined very carefully immediately after birth and during the neonatal period. All cases of neonatal jaundice were noted. The antenatal data (i.e. information collected before birth) collected from the mothers of babies who developed jaundice was compared with the data collected from mothers with babies who did not develop the condition. This is an example of a:"

A retrospective cohort study

A cross-sectional study

A randomized controlled trail

None of the above\

A prospective cohort study