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': 'First change seen in acute inflammation is:September 2009 \nSelect and explain. \nA. Increased permeability, B. Vasodilation, C. Neutrophil migration, D. Vasoconstriction', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ans. D: VasoconstrictionCardinal signs:Rubor (redness) due to dilatation of aeriolesCalor (heat)Dolor (pain) due to pressure on nerve endings by edema fluid and chemical mediator bradykinineTumor (swelling) due to edema.Functio laesa (loss of function) due to inhibition of movement by pain and tissue necrosis.', 'role': 'assistant'}]