Which of the Following Statements Is True of the Ethical

Which of the following statements is true of the ethical issues involved in research?

A) Once the study has begun, participants are not allowed to withdraw their participation.
B) Individuals not capable of understanding the risks of a study (e.g., children) must have a parent, guardian, or other responsible adult make the decision about their participation in the study.
C) Written consent of participation is mandatory under all circumstances, even if participants remain anonymous or if participants are put at risk if it is discovered that they talked with researchers.
D) Researchers are allowed to deceive participants about research aspects that might affect their willingness to participate, but only when such techniques are absolutely essential and justified.