Answer- C. CSF examinationAltered sensorium might be due to raised intracranial tension and lumbar punctare can precipitate the ominous herniation of the brain. So, lumbar puncture (for CSF examination) is not required on emergency evaluation in the above mentioned patient.Altered sensorium in a patient of Turbercular meningitis, who was taking ATT from the last one month maybe due toHepatic encephalopathy secondary to hepatotoxicity of ATT. Hence, LFT should be performed.Diagnosis:Lumbar puncture is cornerstone of diagnosis (should not be done in cases or raised ICT).CSF examination reveals high leukocyte counto (usually predominance of lymphocytes but often with a predominance of neutrophils in the early stage), a protein content of I to 8 g/L (100 to 800 mg/dl) and a low glucose concentration.Culture of CSF is diagnostic in 80% cases.CT or MRI may show hydrocephalus and abnormal enhancement of basal cisterns or ependyma.