What Does the Term 'Colostrum' Refer To

What does the term 'colostrum' refer to?

A) the feedback loop whereby suckling infants have an impact on milk production
B) the main ingredient in infant formula
C) the beneficial fluid that infants glean from the breast before breast milk comes in
D) the 'after-milk' produced when infants are allowed to suckle too freely
E) the bitter substance some people put on their nipples to induce weaning