question: Q:A 33-year-old woman comes to the physician because of a 3-week history of fatigue and worsening shortness of breath on exertion. There is no family history of serious illness. She does not smoke. She takes diethylpropion to control her appetite and, as a result, has had a 4.5-kg (10-lb) weight loss during the past 5 months. She is 163 cm (5 ft 4 in) tall and weighs 115 kg (254 lb); BMI is 44 kg/m2. Her pulse is 83/min and blood pressure is 125/85 mm Hg. Cardiac examination shows a loud pulmonary component of the S2. Abdominal examination shows no abnormalities. Which of the following is the most likely underlying cause of this patient's shortness of breath?? 
  {'A': 'Hypertrophy of interventricular septum', 'B': 'Hyperplasia of pulmonary vascular walls', 'C': 'Blockade of the right bundle branch', 'D': 'Fibrosis of pulmonary interstitium', 'E': 'Calcification of the pulmonary valve'},