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': 'Most common cause of unilateral pedal edema \nSelect and explain. \nA. Pregnancy, B. Lymphedema, C. Venous insufficiency, D. Milroy disease', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Venous insufficiency The most likely cause of leg edema in patients over age 50 is venous insufficiency. Venous insufficiency affects up to 30% of the population, whereas hea failure affects only approximately 1%. The most impoant cause of unilateral pedal edema is venous insufficiency. Milroys disease : The defect in Milroy's disease is present from bih and symptoms are usually first experienced in childhood. The most common problem is one-sided leg swelling, unilateral edema, which is progressive and can affect both legs. Impaired intestinal lymphatics can cause steatorrhea due to impaired transpo of chylomicrons", 'role': 'assistant'}]