This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Endocrinology, Subject name: Physiology
True about oxytocin are all except 
Select and explain. 
A. Synthesized by paraventricular nucleus of hypothalamus, B. Secreted by posterior pituitary, C. Causes uterine contraction of body, D. Causes contraction of upper segment
D: Causes contraction of upper segment
Answer: D: Causes contraction of upper segment 
Explanation: Oxytocin is a hypothalamic hormone stored in and released from the posterior pituitary; it may also be prepared synthetically or obtained from the posterior pituitary of domestic animals. It acts as a powerful stimulant to the pregnant uterus, especially toward the end of gestation, and also causes milk to be expressed from the alveoli into the lactiferous ducts during breastfeeding.Ref: Ganong&;s review of medical physiology; 24th edition; page no: 311