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': "All of the following are true about Raynaud\\'s disease except - \nSelect and explain. \nA. More cormnon in females, B. Positive antinuclear antibodies, C. Most common cause of raynaud's phenomenon, D. Has good prognosis", 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]