This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Radiology
Which of the following is the best choice to evaluate radiologically a posterior fossa tumor? 
Select and explain. 
A. CT scan, B. MRI, C. Angiography, D. Myelography
B: MRI
Answer: B: MRI 
Explanation: MRI is the investigation of choice for all brain tumors.