The correct answer is A. Mitochondria.
Mitochondria are organelles found in most eukaryotic cells. They are responsible for energy production in the cell. Cellular respiration is the process by which cells convert glucose into energy. This process takes place in the mitochondria.
The cytoplasm is the jelly-like substance that fills the cell. It is made up of water, proteins, and other molecules. The cytoplasm is not responsible for energy production.
Chloroplasts are organelles found in plant cells. They are responsible for photosynthesis, the process by which plants convert sunlight into energy. Photosynthesis does not involve cellular respiration.
Therefore, the only organelle that performs cellular respiration is the mitochondrion.