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: Pharmacology
[{'content': 'True statements about vitamin K are: a) Increases the synthesis of factor II, VII, IX and X b) Require exposure to sunlight c) Causes hemolytic anemia in patients with G–6–PD deficiency d) t1/2 is < 6 hour \nSelect and explain. \nA. ab, B. ac, C. bc, D. cd', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Vitamin K\xa0is a group of structurally similar, fat-soluble\xa0vitamins\xa0that the human body requires for\xa0complete\xa0synthesis\xa0of certain proteins that are\xa0prerequisites for blood coagulation\xa0(K from\xa0Koagulation, Danish for "coagulation") and which the body also needs for controlling binding of calcium in bones\xa0and other tissues.\xa0The vitamin K-related modification of the proteins allows them to bind\xa0calcium\xa0ions, which they cannot do otherwise. Without vitamin K,\xa0blood coagulation is seriously impaired, and uncontrolled bleeding occurs. Preliminary clinical\xa0research\xa0indicates that deficiency of vitamin K may weaken bones,\xa0potentially leading to osteoporosis.', 'role': 'assistant'}]