<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 29-year-old woman comes to the emergency room with a 4-day history of fever and worsening cough. She describes bringing up a purulent, yellow sputum when she coughs. The patient has a history of cystic fibrosis and works as an elementary school teacher. The patients temperature is 102.3F 39.1C, blood pressure is 11373 mmHg, pulse is 98min, respirations are 18min, and oxygen saturation is 94 on room air. She is sitting up in bed and sweating. Physical exam reveals bilateral crackles and decreased breath sounds with a dullness to percussion in the right lung base. A chest radiograph is obtained and reveals a right lower lobe pneumonia. Which of the following is the most likely agent?? A: Haemophilus influenzae, B: Influenza virus, C: Pseudomonas aeruginosa, D: Staphylococcus aureus, E: Streptococcus pneumoniae,  <response>: This is a clinical vignette describing a 29-year-old woman with cystic fibrosis who presents with fever, cough, and purulent sputum. She has signs and symptoms of a bacterial pneumonia including fever, productive cough, decreased breath sounds, and dullness to percussion on exam. The chest x-ray shows right lower lobe pneumonia. In patients with cystic fibrosis, the most common bacterial pathogen causing pneumonia is Pseudomonas aeruginosa. Pseudomonas often causes chronic lung infections in these patients due to impaired mucociliary clearance. The purulent sputum also points towards a Pseudomonas infection.Influenza would not cause a productive purulent cough. Haemophilus influenzae and Streptococcus pneumoniae are less likely than Pseudomonas in a patient with cystic fibrosis. Staphylococcus aureus is an uncommon cause of community-acquired pneumonia.C: Pseudomonas aeruginosa 