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: Medicine
[{'content': 'The antibody responsible for heparin induced thrombocytopenia is: \nSelect and explain. \nA. Antiheparin / PF4 antibody, B. Antiheparin / PF2 antibody, C. Antiheparin / GP IIb/IIIa antibody, D. Antiheparin GP Ib/IX antibody', 'role': 'user'}, {'content': 'Answer: A \nExplanation: HIT results from antibody formation to a complex of the platelet specific protein platelet factor 4 and heparin. Ref: Harrisons principles of internal medicine, Edition -18, Page - 967.', 'role': 'assistant'}]