This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cystic fibrosis & Sleep apnea, Subject name: Medicine
What is the most common presentation in cystic fibrosis? 
Select and explain. 
A. Lung infection, B. Meconium ileus, C. Malabsorption, D. Infeility
A: Lung infection
Answer: A: Lung infection 
Explanation: Feature Percentage of cases Acute or persistent respiratory symptoms 50.5 Failure to thrive, malnutrition 42.9 Abnormal stools 35.0 Meconium ileus, intestinal obstruction 18.8 Family history 16.8 Electrolyte acid-base abnormality 5.4 Nasal polyps; sinus disease 2.0 Hepatobiliary disease 0.9