In Designing the Strange Situation, Mary Ainsworth and Her Colleagues

In designing the Strange Situation, Mary Ainsworth and her colleagues reasoned that securely attached infants and toddlers

A) use the parent as a secure base from which to explore in an unfamiliar setting.
B) are just as comforted by an unfamiliar adult as by the parent.
C) combine anger and clinginess when reunited with a parent who has left the room for a time.
D) do not show distress when the parent leaves the room.