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
BCG is used in tumour therapy - 
Select and explain. 
A. Bladder, B. Stomach, C. Oesophagus, D. Colon
A: Bladder
Answer: A: Bladder 
Explanation: Ans. is 'a' i.e., Bladder