This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Clinical Aspects of Neoplasia, Subject name: Pathology
[{'content': 'Which of the following carcinoma most frequently metastasizes to brain - \nSelect and explain. \nA. Small cell carcinoma lung, B. Prostate cancer, C. Rectal carcinoma, D. Endometrial cancer', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Small cell carcinoma of lung Frequency of Nervous system metastasis by common primary tumour. Site of primary tumourBrain %MetastasesLeptomeningeal % MetastasisSpinal cord % CompressionLung402418Breast194124Melanoma10124Gastrointestinal tract7136Genitourinary tract7-18Others171030", 'role': 'assistant'}]