Which of the Following Is an Example of Negative Feedback

Which of the following is an example of negative feedback?

A) During birthing contractions, oxytocin (a hormone) is released and acts to stimulate further contractions.
B) When a baby is nursing, suckling leads to the production of more milk and a subsequent increase in the secretion of prolactin (a hormone that stimulates lactation) .
C) After a blood vessel is damaged, signals are released by the damaged tissues that activate platelets in the blood. These activated platelets release chemicals that activate more platelets.
D) When the body temperature exceeds 37◦C the brain signals the release of sweat to cause evaporative cooling.
E) When a neuron is about to transmit an impulse, opening of voltage-gated ion channels results in the opening of more channels.