Why is the citric acid cycle called a "cycle"?

• A. The acetyl CoA that enters the cycle is regenerated in the last step of the pathway.
• B. NAD⁺ and FAD are recycled.
• C. All of the carbon from glucose is cycled back into the atmosphere as carbon dioxide.
• D. NADH is cycled down the electron transport chain.
• E. The four-carbon acid that accepts the acetyl CoA in the first step of the cycle is regenerated by the last step of the cycle.