Final answer:
The Zidovudine (AZT) trial raises ethical concerns about withholding potentially life-saving treatment from participants in the control group.
Step-by-step explanation:
The Zidovudine (AZT) trial illustrates the ethical problem with the use of placebo control groups because it raises concerns about withholding potentially life-saving treatment from participants in the control group. In the case of AZT, it was the first drug approved for the treatment of AIDS. The trial involved giving some participants AZT while others received a placebo, and those in the control group did not have access to the potentially life-saving treatment. This raises ethical questions about whether it is acceptable to deny participants access to a potentially beneficial treatment.