Which one of the following facilitates birth and maternal bonding?

Oxytocin is a mammalian neurohypophysical hormone. It is produced by the hypothalamus and stored and secreted by the posterior pituitary gland. Oxytocin acts primarily as a neuromodulator in the brain. Oxytocin plays an important role in the neuroanatomy of intimacy, specifically in sexual reproduction, particularly during and after childbirth. It is released in large amounts after distension of the cervix and uterus during labor, facilitating birth, maternal bonding and after stimulation of the nipples, lactation. Both childbirth and milk ejection results from positive feedback mechanism.