Answer:
The correct answer will be option-A.
Step-by-step explanation:
Krebs cycle or tri-carboxylic cycle a series of cyclic chemical reactions taking place in the cell which helps in oxidation of the acetyl-CoA to form energy molecules as reducing energy equivalents.
It is the phase of the aerobic respiration which produces reducing equivalents like NADH and FADH₂ with other by-products like two carbon dioxide (CO₂). It also produces one Guanosine triphosphate (GTP) molecule.
The hydrogen ions are not produced in the cycle directly but are utilized in the conversion of the NAD⁺ to NADH and 2 H⁺ ions used in FAD to FADH₂.
Thus, option-A is the correct answer.