input: The following are multiple choice questions (with answers) about medical knowledge.   **Question:** A patient presented with headache and fever. His investigations revealed hemoglobin of 16g/dl, TLC of 21,000/ uL, platelet count of 3,75,000. His DLC showed Neutrophils (25%), Lymphocytes (20%), Metamyelocytes and myelocytes 40%and eosinophils5%. Which of the following is the next best investigation in this patient?   (A) JAK 2 mutation   (B) EPO level   (C) Philadelphia chromosome   (D) Bone marrow biopsy
output: ['(C) Philadelphia chromosome <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) JAK 2 mutation  (B) EPO level  (C) Philadelphia chromosome  (D) Bone marrow biopsy <> possible answers', '  A patient presented with headache and fever. His investigations revealed hemoglobin of 16g/dl, TLC of 21,000/ uL, platelet count of 3,75,000. His DLC showed Neutrophils (25%), Lymphocytes (20%), Metamyelocytes and myelocytes 40%and eosinophils5%. Which of the following is the next best investigation in this patient? <> context']