The Nurse Recognizes Piaget's Concrete Operational Thinking When

The nurse recognizes Piaget's concrete operational thinking when:

A) A 2-year-old says, "It's night time" when his room is darkened.
B) A 4-year-old refers to the hospital as "my house."
C) A 5-year-old coloring a picture of a puppy says, "This is my puppy."
D) A 7-year-old says, "I am sick because I have germs in my chest."