<prompt> Please answer with one of the option in the bracket. Write reasoning in between . Write answer in between .Q:A 6-year-old boy is brought in by his mother to his pediatrician for headache and nausea. His headaches began approximately 3 weeks ago and occur in the morning. Throughout the 3 weeks, his nausea has progressively worsened, and he had 2 episodes of emesis 1 day ago. On physical exam, cranial nerves are grossly intact, and his visual field is intact. The patient has a broad-based gait and difficulty with heel-to-toe walking, as well as head titubation. Fundoscopy demonstrates papilledema. A T1 and T2 MRI of the brain is demonstrated in Figures A and B, respectively. Which of the following is most likely the diagnosis?? A: Craniopharyngioma, B: Ependymoma, C: Medulloblastoma, D: Pilocytic astrocytoma, E: Pinealoma,  <response>: This is a clinical case involving a 6-year-old boy with headaches, nausea, vomiting, ataxia, and papilledema. The MRI images demonstrate a midline posterior fossa mass. The symptoms of morning headaches, nausea, vomiting, ataxia, and papilledema indicate increased intracranial pressure likely due to obstruction of cerebrospinal fluid flow. The location of the tumor in the posterior fossa along with the patients young age make medulloblastoma the most likely diagnosis. Craniopharyngioma, ependymoma, and pilocytic astrocytoma are less likely given the location. Pinealoma could cause similar symptoms but is very rare in children.C: Medulloblastoma 