Answer: The correct answer is -
B. Because an increase in oxytocin level increases the contractions.
Step-by-step explanation:
A positive feedback occurs when the output enhances or intensifies the original stimulus.
Oxytocin is a hormone and a chemical messenger, called neurotransmitter that is produced by hypothalamus region of the brain. It plays a significant role during labor as it produces uterine contractions, which help in easy expell of baby out of the mother's womb.
An increase in the level of oxytocin results in increased uterine contractions.
Thus, it illustrates a positive feedback mechanism.