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
Measles vaccination to all 9 months - 14 years children is a pa of which WHO strategy? 
Select and explain. 
A. Mop up, B. Catch up, C. Keep up, D. Follow up
B: Catch up
Answer: B: Catch up 
Explanation: <p> Catch up. Park&;s textbook of preventive and social medicine,K.Park,23rd edition,page no:148-149. <\p>