Which of the Following Is Correct for the Energy Equivalent

Which of the following is correct for the energy equivalent of O₂ ?

A) 4.8 kilocalories of energy liberated per litre of O₂ consumed
B) used to indirectly measure the metabolic rate
C) the energy required to raise 1 gm of H₂O 1°C
D) 4.8 kilocalories of energy equivalent per litre o O₂ consumed and used to indirectly measure the metabolic rate