Q. A 20-year-old woman with a known history of cystic fibrosis presents to your clinic with complaints of worsening cough, increased sputum production, and shortness of breath over the past 3 days. The patient also reports feeling feverish. Her temperature is 101.2°F (38.4°C), pulse 100 beats per minute, blood pressure 110/70 mmHg, and respiratory rate 22 per minute. Her oxygen saturation on room air is 96%. Physical examination shows dullness to percussion in the right lower lung field and coarse crackles on auscultation over the same area. Given the patient's medical history and clinical presentation, which of the following organisms is the most likely responsible for this patient's condition?