Determine What Type of Observational Study Is Described

Multiple Choice

Determine what type of observational study is described. Explain.
-Researchers wanted to determine whether there was an association between city driving and stomach ulcers.They selected a sample of 900 young adults and followed them for a twenty-year period. At the start of thestudy none of the participants was suffering from a stomach ulcer. Each person kept track of the number ofhours per week they spent driving in city traffic. At the end of the study each participant underwent tests todetermine whether they were suffering from a stomach ulcer. The researchers analyzed the results todetermine whether there was an association between city driving and stomach ulcers.

A) cohort; Individuals are observed over a long period of time.
B) cross-sectional; Information is collected at a specific point in time.
C) retrospective; Individuals are asked to look back in time.