This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Communicable diseases, Subject name: Social & Preventive Medicine
[{'content': 'Measles vaccination to all 9 months - 14 years children is a pa of which WHO strategy? \nSelect and explain. \nA. Mop up, B. Catch up, C. Keep up, D. Follow up', 'role': 'user'}, {'content': 'Answer: B \nExplanation: <p> Catch up. Park&;s textbook of preventive and social medicine,K.Park,23rd edition,page no:148-149. <\\p>', 'role': 'assistant'}]