This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General pathology, Subject name: Pathology
[{'content': 'Most common primary in brain metastasis is from \nSelect and explain. \nA. Breast carcinoma, B. Lung carcinoma, C. Gastric carcinoma, D. Colo-rectal carcinoma', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Brain metastases occur when cancer cells spread from their original site to the brain. Any cancer can spread to the brain, but the types most likely to cause brain metastases are lung, breast, colon, kidney and melanoma. Brain metastases, or secondary brain tumors, occur in 10 to 30 percent of adults with cancer.', 'role': 'assistant'}]