This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Which among the following shows that pulmonary circulation differs from systemic circulation? 
Select and explain. 
A. Pulmonary vasodilation in hypoxia, B. Pulmonary vasoconstriction in hypoxia, C. Decreased blood volume during systole, D. Increased basal vasoconstrictor tone
B: Pulmonary vasoconstriction in hypoxia
Answer: B: Pulmonary vasoconstriction in hypoxia 
Explanation: The vasoconstrictor response of the pulmonary circulation to low oxygen tension is exact opposite of response of systemic aerioles. The opposite effect in pulmonary vessels occurs in order to distribute the blood flow to better ventilated area and be more effective. This vasoconstriction occurs because of presence of potassium gated channel in pulmonary vessels. Ref: Barst R.J., Rubin L.J. (2011). Chapter 71. Pulmonary Hypeension. In V. Fuster, R.A. Walsh, R.A. Harrington (Eds), Hurst's The Hea, 13e.