Answer : 2. "Lungs"
Explanation :

Answer: B) Lungs Explanation: Emphysema is a condition that involves damage to the walls of the air sacs (alveoli) of the lung i.e, primarily causes shortness of breath due to over-inflation of the alveoli.   First, emphysema causes holes to gradually form inside the lungs' air sacs, thereby weakening their internal structure and inhibiting the exchange of oxygen and carbon dioxide.