Answer: d. Mitochondria
Mitochondria is a powerhouse of a cell. The mitochondria is a functional organelle which, helps in the cellular respiration. It breaks down the sugars present in the food molecules to release energy in the form of ATP.
In the given situation, chemical is added to the cells, the cells are unable to break down the sugar and they die of starvation, this is because of the fact that the chemical has affected the functioning of the mitochondria. Therefore, the cell is incapable of breaking down of sugars.