A 9-month-old infant who cries when the mother leaves is showing

A) separation anxiety.
B) stranger anxiety.
C) anxious attachment.
D) overdependence.

Separation anxiety is the fear or distress that occurs in infants and young children when they are separated from their primary caregiver. Crying when the mother leaves is a common sign of separation anxiety in infants. Choice B, stranger anxiety, refers to the fear or wariness of strangers that usually emerges around 6 months of age but is not specific to when the mother leaves. Choice C, anxious attachment, refers to a pattern of insecure attachment where the child is overly reliant on their caregiver and shows distress when separated, but this is not confirmed in the given scenario. Choice D, overdependence, is not a recognized term in developmental psychology and does not fit the description of the infant's behavior.