Judy DeLoache Used a Scale Model to Hide a Toy

Judy DeLoache used a scale model to hide a toy under a toy couch identical to a life-size couch in the room. A 4-year-old could find the real toy under the life-size couch after realizing the scale model was a copy of the room. According to DeLoache, why were 30-month-olds unable to find the toy in the same way?

A) Delayed development
B) The fact they are still in the preoperational stage
C) Lack of dual representational skills
D) Egocentrism
E) Lack of symbolic understanding