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: Physiology
Energy producing enzymes are located in 
Select and explain. 
A. Rough endoplasmic reticulum, B. Ribosomes, C. Golgi apparatus, D. Mitochondria
D: Mitochondria
Answer: D: Mitochondria 
Explanation: In mitochondria, enzymes for energy metabolism and protein synthesis can be found.