<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 35-year-old man presents to pulmonary function clinic for preoperative evaluation for a right pneumonectomy. His arterial blood gas at room air is as follows:pH: 7.34PaCO2: 68 mmHgPaO2: 56 mmHgBase excess: 1O2 saturation: 89What underlying condition most likely explains these findings?? A: Acute respiratory distress syndrome, B: Bronchiectasis, C: Chronic obstructive pulmonary disease, D: Cystic fibrosis, E: Obesity,  <response>: This is a question about interpreting arterial blood gas results to identify an underlying pulmonary condition. The key findings are an elevated PaCO2 of 68 mmHg, a low PaO2 of 56 mmHg, and an oxygen saturation of 89 on room air. An elevated PaCO2 indicates impaired ventilation and retention of CO2. A low PaO2 indicates impaired gas exchange and hypoxemia. The combination of hypercapnia and hypoxemia with a normal pH points towards a chronic respiratory condition rather than an acute process. Of the choices given, chronic obstructive pulmonary disease COPD best explains these arterial blood gas results. COPD leads to airflow limitation and impaired ventilation resulting in CO2 retention. It also causes destruction of alveolar walls leading to impaired gas exchange and hypoxemia. The other choices do not explain the combination of hypercapnia and hypoxemia.C: Chronic obstructive pulmonary disease 