What Did Main and Weston Conclude from Their Research Regarding

What did Main and Weston conclude from their research regarding the role of mothers and fathers in an infant's attachment and social responsiveness?

A) If the child was securely attached to the mother, quality of attachment to the father had little impact on social responsiveness.
B) Children who were securely attached to the father but not to the mother were less socially responsive than children attached their mothers.
C) Children who were securely attached to both parents were happier and socially responsive.
D) Children were only securely attached to the father if he was residing in the home.