Answer:
Option- A,B and C
Step-by-step explanation:
The Willowbrook Hepatitis study was performed by Dr Krugman in 1955 when they found that the staff and students of Willowbrook State School were found to be affected with the Hepatitis.
He studied the vulnerable population of the school and followed the principles which were outlined in the Belmont report. He used to inject gamma globulin antibodies from the hepatic patients to the other hepatitis patients to treat the disease and the benefits of this disease did not outweighed the risk. Therefore this study was found useful in studying more about hepatitis and classifying the disease into two types A and B.
Thus, Option- A, B and C are correct.