When 1-year-old Andrea tries to talk,her mother talks back;when she smiles,her mother smiles in return.These maternal reactions are most relevant to Andrea's development of

A) a secure attachment.
B) conservation.
C) egocentrism.
D) object permanence.

Maternal responsiveness plays a crucial role in the formation of secure attachment between infants and their caregivers. By responding to Andrea's attempts at communication and mirroring her facial expressions, her mother is providing a safe and nurturing environment for her to develop a secure attachment. Conservation, egocentrism, and object permanence are important developmental milestones, but they do not directly depend on maternal responsiveness.