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: Surgery
[{'content': "A useful though temporary improvement in a patient's ischaemic foot can be attained by giving intravenously \nSelect and explain. \nA. 10% Mannitol, B. 10% Dextrose, C. Dextran 40, D. Dextran 100", 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]