This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General, Subject name: Physiology
Energy production enzymes are located in: 
Select and explain. 
A. Rough endoplasmic reticulum, B. Ribosomes, C. Golgi apparatus, D. Mitochondria
D: Mitochondria
Answer: D: Mitochondria 
Explanation: Ans. (d) Mitochondria(Ref: Ganong, 25th ed/p.36)Mitochondria is involved in the synthesis of energy-rich compound ATP by oxidative phosphorylationAlso called as "powerhouse of the cell"