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: Pathology
[{'content': 'Histamine causes: \nSelect and explain. \nA. Hypertension, B. Vasoconstriction, C. Vasodilation, D. Tachycardia', 'role': 'user'}, {'content': 'Answer: C \nExplanation: The main actions of histamine are:\xa0\n\nVasodilation\nIncreased vascular (venular) permeability\nItching\xa0\nPain\n\nStimulation of mast cells and basophils also releases products of arachidonic acid metabolism including the release of slow reacting substances of anaphylaxis (SRS-As).\xa0\nThe SRS-As consist of various leukotrienes (LTC4, LTD4 and LTE4).\nMohan H. Textbook of pathology. Jaypee Brothers Medical Publishers; 2015. Edition 7. Page 123', 'role': 'assistant'}]