Answer:
The correct answer is prospective cohort study.
Step-by-step explanation:
A prospective cohort study is a type of observational research used in epidemiology to establish relationship between exposure and outcome.
Essentially, investigators follow two populations (one exposed to the factor under study and one not exposed) over time until the outcome occurs.
With this type of research, incidence (probability of occurrence) can be calculated, because a timeline is present.