Which of the following refers to unexplained crying in infants, often occurring in the late afternoon or evening?

Colic describes a situation commonly observed in infants where they exhibit unexplained and excessive crying, particularly during the late afternoon or evening. This phenomenon typically starts around a few weeks of age and can last until they are about three to four months old. While the reasons for colic are not fully understood, it is characterized by severe distress in the infant, and it often leaves parents feeling helpless. The crying associated with colic is noted for occurring in episodes, lasting for at least three hours a day, three days a week, for three weeks or longer.

Normal crying refers to the typical, healthy crying behavior of infants as a means of communication, signaling needs such as hunger, discomfort, or the desire for comfort. Separation anxiety occurs later in development when infants become more aware of their surroundings and may react negatively to being separated from their caregivers. Excessive distress crying, while similar to colic, is not a defined medical term and may not encapsulate the specific characteristics associated with colic. Thus, colic is the most precise term to describe this phenomenon of unexplained evening crying in young infants.