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
Which of the following is the most common origin of cerebral metastasis? 
Select and explain. 
A. Lung cancer, B. Breast cancer, C. Melanoma, D. Colon cancer
A: Lung cancer
Answer: A: Lung cancer 
Explanation: Lung: 40%
Breast : 10 - 30%
Melanoma : 5 - 15%
Unknown : 15%