<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 29-year-old man presents for the evaluation of infertility. He has a history of recurrent lower respiratory tract infections, productive cough, abdominal pain, and diarrhea. Physical examination reveals clubbing and bilateral crackles on chest auscultation. Chest X-ray reveals increased pulmonary markings and peripheral bronchi with a tram track appearance. Which of the following pathophysiologies is responsible for the patients condition?? A: Bronchial hypersensitivity, B: Fibrosis of the lung parenchyma, C: Defective chloride transport, D: Abnormal ciliary motion, E: Gluten hypersensitivity,  <response>: This is a medical question asking about the pathophysiology responsible for a patients condition based on the clinical findings described. The key findings are recurrent respiratory infections, productive cough, clubbing, crackles on lung exam, and chest X-ray showing increased markings and bronchiectasis. This constellation of findings is classic for cystic fibrosis, which is caused by defective chloride transport.C: Defective chloride transport 