A 50-year-old HIV seropositive male presented to the ER with multiple episodes of generalized tonic-clonic seizures. Patient is not on HAA. CD4 count was done and it was 45/ microL. O/E, Mildly arousable Disoriented No nuchal rigidity or focal neurological deficits Gadolinium enhanced MRI and MR spectroscopy were conducted. Which is the most appropriate drug to be given in the above condition: –