This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Disorders of the Respiratory Tract, Subject name: Pediatrics
Alpha-1- antitrypsin deficiency presents as? 
Select and explain. 
A. Emphysema, B. Bronchitectasis, C. Empyema, D. Bronchogenic carcinoma
A: Emphysema
Answer: A: Emphysema 
Explanation: Ans. (a) EmphysemaRef: Robbins 8thEdn /684y 685, Harrison 18,hed chapter 309, Nelson Textbook of Pediatrics, 18th ed chapter 390