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': 'Lymphangiography of the leg is performed by ? \nSelect and explain. \nA. Injecting sodium diatrizoate retrogradely under pressure into a small vein on the dorsum of the foot, B. Dissecting lymphatics through an incision on the dorsum of the foot, C. The use of an infusion pump, D. All', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Dissecting lymphatics through an incision on the dorsum of the foot", 'role': 'assistant'}]