This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Glycolysis, Subject name: Biochemistry
In Anaerobic glycolysis, there is gain of - 
Select and explain. 
A. 2 ATP + 2 NAD, B. 2 ATP, C. 2 ATP + 2 NADH, D. 4 ATP + 2 FADH2
B: 2 ATP
Answer: B: 2 ATP 
Explanation: Net gain in anaerobic glycolysis is only - 2 ATP. - 2 NADH are produced also (Glyceraldehyde-3-P dehydrogenase step) - But 2 NADH are used also (Lactate dehydrogenase step). Similarly - 2 NAD are produced also (Lactate dehydrogenase step) - But 2 NAD are used also (Glyceraldehyde-3-P dehydrogenase step). So there is no net gain of NADH or NAD.