When a poison such as cyanide blocks the electron transport chain, glycolysis and the citric acid cycle also eventually stop working. Which of the following is the best explanation for this?

• A. A high level of NADH is present in the cell.
• B. The uptake of oxygen stops because electron transport was inhibited.
• C. Electrons are no longer available from the electron transport chain to power glycolysis and the citric acid cycle.
• D. They run out of ADP.
• E. NAD⁺ and FAD are not available for glycolysis and the citric acid cycle to continue.