Q. A 56-year-old man visits his primary care physician with complaints of worsening shortness of breath, dry cough, and fatigue over the last two months. He has a 10-year smoking history but quit five years ago. He occasionally drinks alcohol and has no significant family history of lung diseases. His vital signs are as follows: temperature 98.6°F (37°C), blood pressure 135/85 mmHg, heart rate 95 beats/min, respiratory rate 22 breaths/min, and oxygen saturation 93% on room air. The patient is an avid bird enthusiast and has several pet birds at home. Bronchoalveolar lavag shows a lymphocytosis of 55% with negative mycobacterial stains and cultures. What is the most likely diagnosis for this patient's symptoms?