Which of the Following Is a Reason for Grandparents to Be

Which of the following is a reason for grandparents to be able to relate to grandchildren in a more relaxed way than parents?

A) They have a greater fund of child-rearing experience than the parents.
B) They only have to spend time with the kids for short amounts of time, and so they rarely see the children misbehaving.
C) They are not really respected by the grandchildren as an authority figure, and so they do not have to care as much as the parents do.
D) They know that their child-rearing skills are better than the parents', so they can act without worrying about being wrong.