The Term "Concrete" Is Used to Describe Concrete Operations Because

The term "concrete" is used to describe concrete operations because

A) understating reversibility at this stage is so hard (like concrete) .
B) once a child focuses on one aspect of a task, his thinking appears to be unmovable (set in stone or concrete) .
C) the path of understanding is paved with challenges (like a concrete road) .
D) individuals in this stage can mentally manipulate objects as long as they are present (concrete example) .