Final answer:
The statement that the Public Health Service allowed the Tuskegee study participants to receive penicillin when it became available is false; participants were denied effective treatment despite its availability.
Step-by-step explanation:
The false statement about the Tuskegee study is option c. The Tuskegee study is a grave example of unethical medical research practices. The participants were not treated with penicillin, although it had become the recognized treatment for syphilis by 1947, contrary to the claim in statement c. The study was carried out on African American men under the guise of treating "bad blood," but in reality, no proper treatment was ever provided, and the participants were not informed they had syphilis. The study became a catalyst for ethical reforms in human subjects research, resulting in the establishment of the National Research Act of 1974 and the creation of the National Commission for the Protection of Human Subjects of Biomedical and Behavioral Research.