Cellular respiration is the way to convert chemical energy to ATP out of O2 and other nutrients. Both plant and animal cells undergo this process. The specific organelle that serves as the site of cellular respiration is the the mitochondrion. It act in the production of ATP. Mitochondria is where chemical energy are located to provide power needed by the cell.
Endoplasmic reticulum plays a role in the production of protein. Cell membrane gives protection to the cell by providing a fixed environment inside it. Nucleus is the one that controls and regulates the cell's activities.
Answer - Option B - mitochondrion