The Tuskegee Syphilis Study Has Been a Symbol of Unethical

The Tuskegee syphilis study has been a symbol of unethical research because the researchers

A) injected African-American men with the disease.
B) exposed African-American men to infected prostitutes in order to infect them.
C) failed to treat infected African-American men even after effective treatments were available.
D) encouraged infected African-American men to have unprotected sex with their partners.
E) failed to tell infected African-American men that they had syphilis.