Answer:
The correct answer will be option-NADH generated from the citric acid cycle.
Step-by-step explanation:
During cellular respiration, few ATP molecules are synthesized by substrate-level phosphorylation in glycolysis and citric acid cycle.
The process also produces high energy equivalents which are NADH and FADH₂ during the citric acid cycle. Two pyruvate molecules generate 6 NADH and FADH₂ molecules. These molecules release electron and hydrogen during the electron transport chain which is utilized to generate the ATP.
Each NADH produces 3 ATP molecule whereas FADH₂ molecule produces 2 ATP molecules. Since 6 NADH (6x3=18 ATP) produced and 2 FADH₂ (2x2).
Thus, NADH provides the highest amount of ATP molecules.