Final answer:
Infants with resistant attachment display clingy behavior before separation and reject their caregiver upon reunification, often due to inconsistent parental responsiveness.
Step-by-step explanation:
Infants who seek closeness to their mother before separation but display angry behavior when she returns are classified as having a resistant attachment pattern. This attachment style is characterized by the child's tendency to show clingy behavior before separation and then rejection of the parent upon their return. During the Strange Situation, these children are highly distressed during the separation and are difficult to comfort, even when the caregiver returns. The inconsistency in the caregiver's responsiveness to the child's needs often leads to resistant attachment.