In the Tuskegee Syphilis Experiment, What Did the Medical Staff

In the Tuskegee Syphilis Experiment, what did the medical staff at Tuskegee University do?

A) They provided low-cost care for men infected with venereal disease during World War II
B) They discovered a new strain of syphilis, but did not report it to the Center for Disease Control.
C) They used unauthorized, experimental treatments for syphilis.
D) They left men diagnosed with syphilis go untreated so they could follow the disease.