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
Sources of NADPH are : 
Select and explain. 
A. Malic enzyme, B. Cytoplasmic isocitrate dehydrogenase, C. Pentose phosphate pathway, D. All of the above
D: All of the above
Answer: D: All of the above 
Explanation: These are the only 3 sources of NADPH that are currently known.