Answer:
a) withheld information from test subjects about their condition
Explanation:
The Tuskegee syphilis study which was carried between 1932-1972 in the Macon County, Alabama on the African-Americans infected from syphilis.
The U.S. Public Health Service started the study promising the infected persons that they will receive the benefits from the studies like a healthy meal, proper antibiotic medication and other benefits.
But the U.S Public Health Service failed to provide the services mainly the medication in which antibiotic penicillin which could treat the disease was not provided to the patient. As a result of this, syphilis continued in their generations also and people and about 100 subjects died.
They were told that they had bad blood which cannot be treated and thus in 1972, this raised a question over this issue related to ethics as to why the penicillin was not provided as well why the person was kept away from the reality.
Thus, Option-A is the correct answer.