The Krebs cycle (also known as the citric acid cycle) produces the most NADH during cellular respiration.

Here's why:

* Glycolysis, the first stage, produces only 2 NADH molecules per glucose molecule.

* The Krebs cycle, the second stage, produces 6 NADH molecules per glucose molecule (3 per turn of the cycle, and the cycle occurs twice per glucose).

* Electron transport chain, the final stage, does not produce NADH but utilizes it to generate ATP.

Therefore, the Krebs cycle is the most prolific producer of NADH in cellular respiration.