<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 49-year-old woman comes to the physician because of a 4-month history of a dry cough and shortness of breath on exertion. She also reports recurrent episodes of pain, stiffness, and swelling in her wrist and her left knee over the past 6 months. She had two miscarriages at age 24 and 28. Physical examination shows pallor, ulcerations on the palate, and annular hyperpigmented plaques on the arms and neck. Fine inspiratory crackles are heard over bilateral lower lung fields on auscultation. Which of the following additional findings is most likely in this patient?? A: Decreased A-a gradient, B: Decreased right atrial pressure, C: Increased airway resistance, D: Decreased diffusing capacity, E: Increased lung compliance,  <response>: This is a clinical vignette describing a 49-year-old woman with a 4-month history of dry cough, shortness of breath, joint pain and swelling, prior miscarriages, physical exam findings of pallor, oral ulcers, skin lesions, and crackles on lung exam. The key findings are dry cough, shortness of breath, joint symptoms, prior miscarriages, oral ulcers, skin lesions, and lung crackles. This suggests an autoimmune condition like rheumatoid arthritis or systemic lupus erythematosus. The question asks for an additional finding that is most likely. The choices describe different pulmonary function test results. Decreased diffusing capacity would indicate impaired gas transfer in the lungs, which fits with the clinical picture of autoimmune lung involvement.D: Decreased diffusing capacity 