All of the Following Statements Make the Case for a Fifth

All of the following statements make the case for a fifth stage of cognitive development except

A) the fact that the thinking of young adults is more egocentric than the thinking of adolescents.
B) that young adults are more likely to see the world in shades of gray.
C) that theorists such as Piaget have proposed a postformal stage of cognitive development based on comparisons of adolescents and young adults.
D) all of these