Answer:
A. The Public Health Service Tuskegee Study of Untreated Syphilis in Negro Male
Explanation:
The Public Health Service Tuskegee Study of Untreated Syphilis in Negro Male was a cohort study between 1932 to 1972 by the Public Health Service. The study was however unethical as subjects were not to;d of the real nature or objective of the study, they were told that they were receiving free medical treatment. However, in 1972 the real intent of the study was exposed by Peter Buxtun, this led to the establishment of the National Research Act in 1974.