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: Pharmacology
[{'content': 'Which one is a contraindication to the use of ergot derivatives : \nSelect and explain. \nA. Migraine, B. Hyperprolactinemia, C. Obstructive vascular disease, D. Postpartum hemorrhage', 'role': 'user'}, {'content': 'Answer: C \nExplanation: None', 'role': 'assistant'}]