A nurse is caring for an 18-month-old toddler who has been hospitalized for 10 days. After the toddler's mother leaves the room, the nurse observes the toddler sitting quietly in the corner of the crib, sucking her thumb. When the nurse approaches the crib, the toddler turns away from the nurse. The nurse should understand that these behaviors indicate which of the following developmental reactions?

Choice A reason:Developing autonomy is a part of normal toddler development where they seek independence and control over their environment. The described behavior does not indicate a quest for autonomy but rather a response to stress or discomfort.Choice B reason:Resentment toward the mother is unlikely in this context. Toddlers may show signs of separation anxiety or distress when a parent leaves, but resentment is a complex emotion that is not typically within the emotional range of an 18-month-old.Choice C reason:An anxiety reaction is possible, as hospitalization can be a stressful experience for a toddler. However, the specific behaviors of thumb-sucking and turning away when approached are more indicative of regression, a return to earlier stages of development, as a coping mechanism.Choice D reason:Regression is a defense mechanism in which a child reverts to behaviors that are typical of an earlier developmental stage when faced with stress. Hospitalization can be a traumatic experience for a toddler, and behaviors such as thumb-sucking and withdrawal are common regressive responses as they seek comfort.