Why Did Piaget Prefer the Term Schemes Rather Than the Term

Why did Piaget prefer the term schemes rather than the term concepts to discuss the organization of thoughts?

A) because the term can be used to describe interrelated groups of actions as well as ideas, which is useful especially when describing infant intelligence
B) because schemes always refer to plans rather than ideas
C) because schemes suggest a manipulation on objects, not the object itself
D) because concepts imply intelligence, and Piaget did not want to attribute intelligence to infants