To test the efficacy of a health education program in reducing the risk of food-borne and water-borne diseases, two Peruvian villages were given an intensive health education program. At the end of two years, the incidence rates of important water-borne and food-borne diseases in these villages were compared with those in two similar control villages without any education program.
A. Cross-sectional study
B. Case-control study
C. Prospective cohort study
D. Retrospective cohort study
E. Clinical trial
F. Community trial