Which Criticism Is Associated with Each of Piaget's Cognitive Stages,Erikson's

Which criticism is associated with each of Piaget's cognitive stages,Erikson's psychosocial stages,and Kohlberg's stage theory of moral development

A)  People are often functioning at more than one "stage" at the same time, suggesting that stages are not sequential. 
B)  Progress through stages is universal, which suggests that culture and learning have little effect. 
C)  Stages described by the theorists are not valid categories because they are not associated with particular abilities or skills. 
D)  Stage theories focus on individual differences rather than common developmental patterns.