input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A 40-year-old man comes to the physician because of shortness of breath, double vision, and fatigue for the past 4 weeks. He has no history of serious medical illness and takes no medications. Physical examination shows drooping of the eyelids bilaterally. He is unable to hold his arms up for longer than 3 minutes. A CT scan of the chest shows an anterior mediastinal mass with smooth contours. A photomicrograph of a specimen from the mass is shown. Which of the following immunologic processes normally occurs in the region indicated by the arrow?   (A) B-cell maturation   (B) V(D)J recombination   (C) Thymocyte formation   (D) Negative selection
output: ['(D) Negative selection <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) B-cell maturation  (B) V(D)J recombination  (C) Thymocyte formation  (D) Negative selection <> possible answers', '  A 40-year-old man comes to the physician because of shortness of breath, double vision, and fatigue for the past 4 weeks. He has no history of serious medical illness and takes no medications. Physical examination shows drooping of the eyelids bilaterally. He is unable to hold his arms up for longer than 3 minutes. A CT scan of the chest shows an anterior mediastinal mass with smooth contours. A photomicrograph of a specimen from the mass is shown. Which of the following immunologic processes normally occurs in the region indicated by the arrow? <> context']