Read the following passage: "The process of cellular respiration is how organisms convert glucose into adenosine triphosphate (ATP), the primary energy currency of the cell. This complex metabolic pathway occurs in several stages. Glycolysis, the first stage, takes place in the cytoplasm and breaks down glucose into two molecules of pyruvate, producing a small amount of ATP and NADH. Next, pyruvate is converted to acetyl-CoA and enters the Krebs cycle (or citric acid cycle) in the mitochondrial matrix, generating more ATP, NADH, and FADH2. The final and most productive stage is oxidative phosphorylation, which occurs in the inner mitochondrial membrane. Here, the electron transport chain uses the NADH and FADH2 from previous stages to create a proton gradient, which then drives ATP synthase to produce a large quantity of ATP. Oxygen acts as the final electron acceptor in this chain; without it, this stage cannot proceed efficiently, severely limiting ATP production. This entire process is fundamental for sustaining life, powering everything from muscle contraction to protein synthesis." What is the role of oxygen in the final stage of cellular respiration?

1. ATo generate ATP and NADH in the Krebs cycle
2. BTo convert pyruvate into acetyl-CoA
3. CTo act as the final electron acceptor in the electron transport chain
4. DTo break down glucose into pyruvate