A nurse is assessing a postpartum client for signs of postpartum depression. Which of the following symptoms is most indicative of postpartum depression rather than normal postpartum adjustment?

Feeling anxious about the baby's health and well-being, but still able to care for the baby effectively

Experiencing occasional mood swings and irritability while adjusting to the new role of motherhood

Feeling overwhelmed and having difficulty sleeping due to the demands of a newborn

Persistent feelings of sadness, severe fatigue, and loss of interest in activities, including caring for the baby