The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 60-year-old man comes to the physician because of a 2-month history of cough productive of yellow sputum with occasional streaks of blood. He has a history of pulmonary tuberculosis. He is afebrile. Pulmonary examination shows inspiratory crackles at the left infraclavicular area. An x-ray of his chest shows a radiopaque mass in the left upper lung lobe that shifts upon repositioning. A sputum sample does not grow acid-fast bacteria despite multiple cultures. Which of the following is the most likely cause of this patient's condition?   (A) Asbestos inhalation   (B) Neoplastic transformation   (C) Opportunistic colonization   (D) Abscess formation
['(C) Opportunistic colonization <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Asbestos inhalation \n (B) Neoplastic transformation \n (C) Opportunistic colonization \n (D) Abscess formation <> possible answers', "  A 60-year-old man comes to the physician because of a 2-month history of cough productive of yellow sputum with occasional streaks of blood. He has a history of pulmonary tuberculosis. He is afebrile. Pulmonary examination shows inspiratory crackles at the left infraclavicular area. An x-ray of his chest shows a radiopaque mass in the left upper lung lobe that shifts upon repositioning. A sputum sample does not grow acid-fast bacteria despite multiple cultures. Which of the following is the most likely cause of this patient's condition? <> context@"]