This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Hematology, Subject name: Pharmacology
[{'content': 'Which of the following has proved antithrombotic \nSelect and explain. \nA. Gelatin, B. Dextran 40, C. Dextran 100, D. Hetastarch', 'role': 'user'}, {'content': 'Answer: B \nExplanation: refer KDT 6/e p622 Dextran 40 and 70 interferes with coagulation and platelet function and thus prolong bleeding time and so is not used in hyperfibrinogenic ,thrombocytopenia or in presence of bleeding', 'role': 'assistant'}]