Santiago Is a Clinical Psychologist

Santiago is a clinical psychologist. His knowledge and skills might be most relevant for the legal system in which one of these cases?

A) When evaluating the state of mind of a teenager who brought guns to school.
B) When deciding whether jurors understand jury instructions correctly.
C) When assessing a mentally ill defendant's competency to stand trial.
D) When studying how the type of interrogation is related to the likelihood of false confession.