A 38-year-old woman from Mumbai is admitted with acute meningitis. CSF analysis shows: protein 180 mg/dL, glucose 25 mg/dL (serum glucose 95 mg/dL), WBC 450/μL (90% neutrophils), and Gram stain reveals Gram-positive diplococci. Blood culture is positive for *Streptococcus pneumoniae*. The patient has no history of penicillin allergy. Which antibiotic regimen is most appropriate for pneumococcal meningitis?