A 28-year-old woman with limited cutaneous systemic sclerosis presents with a 6-month history of progressive dyspnea on exertion. She denies orthopnea, peripheral edema, or chest pain. Physical examination reveals sclerodactyly and microstomia but no crackles on lung auscultation. Pulmonary function tests demonstrate: FVC 58% predicted, FEV1 55% predicted, FEV1/FVC 0.94, and DLCO 42% predicted. High-resolution CT of the chest shows basilar and bibasilar reticular opacities with traction bronchiectasis. Which of the following best explains the disproportionate reduction in DLCO relative to the reduction in FVC in this patient?

1. A)Impaired alveolar ventilation due to respiratory muscle weakness
2. B)Loss of alveolar-capillary surface area from parenchymal fibrosisGABARITO
3. C)Reduced pulmonary capillary blood volume from pulmonary arterial hypertension
4. D)Aspiration-induced bronchiolitis obliterans from esophageal dysmotility
5. E)Acute exacerbation of interstitial pneumonia causing diffuse alveolar damage