All of the Following Are True About the Concrete Operational

All of the following are true about the concrete operational period EXCEPT:

A) most children enter the concrete operational period around 7 years of age and move to the next stage by age 12
B) the concrete operational child has acquired the mental operator of reversibility
C) upon entering concrete operations, the child is able to smoothly use identity and compensation across all tasks
D) the concrete operational child starts to respond correctly to conversation and classification tasks