Oxytocin Is Thought to Play an Important Role in the Development

Oxytocin is thought to play an important role in the development and expression of maternal behavior, as suggested by the observation that maternal behaviors in various animal species can be disrupted by administering oxytocin antagonists. However, maternal behaviors can be seen in non-nursing mothers and also in mothers of adopted children. The best interpretation of these results is that

A) previous studies implicating oxytocin in maternal behavior were incorrect; it plays no role in maternal behavior.
B) oxytocin may contribute to development of maternal behavior, but other mechanisms are likely to be involved.
C) prostaglandin, rather than oxytocin, is the hormone most responsible for the expression of maternal behavior.
D) the biological mechanisms underlying maternal behavior develop during pregnancy and are not dependent upon whether a mother breast-feeds or not.
E) maternal behavior is not biologically determined.