A nurse places some x-ray contrast the toddler is to drink in a small cup instead of a large cup. Which concept of a toddler's preoperational thinking is the nurse using?

A) Inability to conserve
B) Magical thinking
C) Centration
D) Irreversibility

The nurse is using the toddler's inability to conserve. This is when the toddler is unable to understand the idea that a mass can be changed in size, shape, volume, or length without losing or adding to the original mass. Instead, toddlers judge what they see by the immediate perceptual clues given to them. A small glass means less amount of contrast. Magical thinking is believing that thoughts are all-powerful and can cause events. Centration is focusing on one aspect rather than considering all possible alternatives. Irreversibility is the inability to undo or reverse the actions initiated, such as being unable to stop doing an action when told.