The correct answer is oxygen.
Cellular respiration refers to an array of metabolic reactions and procedures, which occurs in the cells of species to transform biochemical energy from nutrients into ATP and then discharge waste products.
Cellular respiration is regarded as an exothermic redox reaction that discharges heat. The overall reaction takes place in an arrangement of biochemical phases, the majority of which are redox reactions.
The nutrients, which are generally utilized by the plant cells in respiration comprise amino acids, sugar, and fatty acids, and the most usual oxidizing agent or electron acceptor is molecular oxygen.