Which of the Following Would Violate the Principles of Piaget's

Which of the following would violate the principles of Piaget's theory?

A) if identical twins reached the preoperational stage at different times
B) if more intelligent children went through the stages faster than less intelligent children
C) if a gifted child skipped the concrete operational stage and went directly to the formal operational stage
D) if a child went through a revolutionary change of thought at two years of age