All but Which of the Following Are Examples of Double-Blind

Multiple Choice

All but which of the following are examples of double-blind studies?

A) medical experiments where a new drug is tested; one group gets the new drug, the other gets a placebo, and the researcher does not know who got which drug
B) domestic violence studies where intervention is designed to reduce repeat offenses by focusing upon victim strategies when the victim does not know whether he or she is in the control or experimental group
C) any study where the researchers and the subjects do not know whether they are in the experimental or control groups
D) any study where the researchers know who is in the experimental and control groups but promise not to tell the subjects