Number Constancy (Or Conservation)has All of the Following Characteristics Except

Number constancy (or conservation) has all of the following characteristics except:

A) students who do not possess number constancy or conservation cannot progress to more complex mathematical ideas.
B) students can only learn number constancy or conservation if allowed to use manipulatives.
C) students can be taught number constancy or conservation by their teachers and parents.
D) students can be interviewed using Piaget's protocol to determine if they understand conservation of quantities.