What triggers the neuroendocrine reflex for milk secretion during lactation?

The neuroendocrine reflex for milk secretion during lactation is primarily triggered by sensory nerve fibers located in the areola, which is the dark area surrounding the nipple. When a baby breastfeeds, the infant's suckling action stimulates these sensory nerve fibers, sending signals to the hypothalamus and subsequently prompting the release of hormones such as oxytocin. Oxytocin is crucial as it facilitates the let-down reflex, allowing milk to be ejected from the mammary glands into the milk ducts.

This mechanism highlights the importance of physical stimulation in initiating milk release, which is a vital aspect of the breastfeeding process. While other factors such as the infant's cry, physical touch, or even the thought of breastfeeding can influence a mother’s milk let-down reflex, the direct activation of the neuroendocrine pathways is triggered specifically by the sensory input from the areola during breastfeeding. This makes option C the most accurate answer in this scenario.