All but Which of the Following Have Been Put Forth

Multiple Choice

All but which of the following have been put forth as criticisms of Piaget's theory?

A) His research techniques were not rigorous enough.
B) He underestimated abilities of younger children.
C) Development is really more continual and gradual than he proposed.
D) He did not take cultural differences into account.
E) He failed to account for changes in cognitive development that occur across different stages.