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: Surgery
A metastatic carcinoma in the brain of an adult, most often comes from primary in the 
Select and explain. 
A. Stomach, B. Ovary, C. Oral cavity, D. Lung
D: Lung
Answer: D: Lung 
Explanation: Ans. is 'd' i.e. Lung