Final answer:
The energy-releasing organelle in animal cells is the mitochondria. They undergo c) cellular respiration to convert nutrients into ATP, providing energy for the cell. Hence, c) is correct.
Step-by-step explanation:
The energy-releasing organelle found in animal cells is the mitochondria. Mitochondria are responsible for cellular respiration, which is the process of converting energy stored in nutrients into adenosine triphosphate (ATP), the cell's main energy source.
The ATP produced by mitochondria is used by cells for various functions, such as muscle contraction and nerve cell activity.