Limitations on the Number of Adults Who Reach the Formal

Limitations on the number of adults who reach the formal operational level,coupled with what finding,lend credence to Piaget's belief that moral development is limited by cognitive development?

A) Many children at the preoperational level do the right thing,but only out of fear of punishment.
B) Stephen is at the formal operational stage and doesn't tell on his friend for shoplifting because he understands that his friend is just pretending.
C) Phil is at the concrete level and only behaves in class when the teacher is around.
D) Most individuals don't reach the postconventional level.