You are answering a USMLE-style medical question. Question: A 25-year-old male is hospitalized for acute agitation, photophobia, and dysphagia. His parents report that he has been experiencing flu-like symptoms for one week prior to hospital admission. Five weeks ago, the patient was in Mexico, where he went on several spelunking expeditions with friends. The patient ultimately becomes comatose and dies. Autopsy of brain tissue suggests a viral infection. The likely causal virus spreads to the central nervous system (CNS) in the following manner: Options: A) Hematogenous dissemination to the meninges B) Retrograde migration up peripheral nerve axons C) Reactivation of virus previously latent in dorsal root ganglia D) Infection of oligodendrocytes and astrocytes Reply with ONLY the letter of the correct answer (A, B, C, or D). No explanation.