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: Medicine
Which of the following is the most common CNS tumor associated with HIV infection? 
Select and explain. 
A. Lymphoma, B. Glioma, C. Astrocytoma, D. Medulloblastoma
A: Lymphoma
Answer: A: Lymphoma 
Explanation: Answer is A (Lymphoma): The most common neoplasm in the central Nervous System (CNS malignancy) in HIV positive patients is primary CNS Lymphoma. 'Primary CNS Lymphoma is the most common neoplasm of the CNS in HIV positive patients'. - 'Radiology of AIDS' (Springer 2001)/69 Primary CNS Lymphoma is the most common CNS oppounistic malignancy in patients with HIV infection'. Spiral Manual of Allergy & Immunology 4th/439