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: Biochemistry
ATP synthetase is a marker of ? 
Select and explain. 
A. Golgi apparatus, B. Mitochondria, C. Cytosol, D. Endoplasmic reticular
B: Mitochondria
Answer: B: Mitochondria 
Explanation: Ans. is 'b' i.e., Mitochondria