The correct option is A Mitochondria
Mitochondria are called as the power house of the cell because they manufacture energy in the form of ATP in a cell during aerobic respiration. Glycolysis occurs in cytoplasm and converts glucose into two molecules of pyruvic acids. Pyruvic acid molecules are burnt completely inside the mitochondria in Krebs cycle and ATP is produced. The enzymes of Krebs cycle are present in the mitochondrial matrix. However, enzymes of mitochondrial electron transport chain are present on the inner mitochondrial membrane.