A Researcher Is Least Likely to Encounter Legal Liability in Which

A researcher is least likely to encounter legal liability in which of the following situations?

A) In an observational study, you see juveniles spray-painting walls at their school, and you say nothing.
B) You watch one of your subjects deal drugs on the corner, and you alert him when a police car turns the corner.
C) One of your subjects tells you he committed a rape, and you do not tell anyone even though you know what he told you is true.
D) You refuse to reveal confidential information under a claim of immunity.