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
Definitive diagnosis of oral cancer is made by 
Select and explain. 
A. Complete radiographic survey, B. Biopsy, C. Exfoliative cytology, D. Pantograph
B: Biopsy
Answer: B: Biopsy 
Explanation: None