According to Piaget, Young School-Age Children, Up to Age 7

According to Piaget, young school-age children, up to age 7 years, are making a transition to concrete operational thought. A nurse identifies that an example of this would be

A) A child, upon hearing a parent arrange for a babysitter, becoming upset because it means his or her parents are going to leave for the evening.
B) A child becoming more secure about the limits of his or her acceptable behavior.
C) A child no longer believing that an adult dressed in a mouse suit is a giant mouse.
D) A child becoming interested in politics, environmental issues, and social justice.