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: Pathology
[{'content': 'Which carcinoma metastases to heart?a)  Ca breastb) Ca stomach c)  Ca lungd)  Ca urinary bladder  e) Osteosarcoma \nSelect and explain. \nA. a, B. bc, C. ac, D. b', 'role': 'user'}, {'content': 'Answer: C \nExplanation: "Although cardiac metastases occur in 1-20% of all tumor types, the relative incidence is especially high in\xa0malignant melanoma and, to a somewhat lesser extent, in leukemia and lymphoma. In absolute terms, the\xa0most common primary originating sites of cardiac metastases are carcinoma of the breast and lung,\xa0reflecting the high incidence of these cancers. Cardiac metastases almost always occur in the setting of\xa0widespread primary disease, and most often either primary or metastatic disease exists elsewhere in the\xa0thoracic cavity"\n—\xa0Harrison 17th/1497\n"The most frequent tumors involving the heart as metastases are carcinomas of the lung & breast,melanomas, leukemias & lymphomaf\n—\xa0Robbins 7tb/614\nTable (CSDT 11th/ 434):', 'role': 'assistant'}]