This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
[{'content': 'Monday disease is seen with \nSelect and explain. \nA. Beta blockers, B. Nitrates, C. Calcium channel blockers, D. Potassium channel openers', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Nitrates because of tolerance produce Monday headache in workers working in nitrate industry which gradually subsides by Friday. Ref: Katzung 12th ed.', 'role': 'assistant'}]