Indirect principal offenders, also known as indirect perpetrators, refer to the execution of crimes by using others as props, and the user realizes his criminal intention by using the instrumental behavior of the user. The user and the user do not constitute a joint crime. It includes the following two situations: one is the use of persons without criminal responsibility to commit crimes; the other is the use of other people's negligent or unknowing behavior to commit crimes. According to the above definitions, Which of the following acts of A are indirect principals:. ['A picks up the relationship between B and C, causing B to be severely injured in the anger. A. B, and C are all persons with full criminal responsibility.', 'A instigates a mental patient. B slashes with a knife C. A. C is a person with full criminal responsibility, and B is a person without criminal responsibility.', 'Employee A sends Party B to beat Party C, who has been owed money, and promises to give it benefits, and Party B then hurts Party A. Party A. Party B, and Party C are all persons with full criminal responsibility.', 'A asks his under-aged child to sue C, and he does not expect that the facts fabricated by B are exactly the facts of C. A. C is a person with full criminal responsibility, and B is a person without criminal responsibility.']