$\mathrm{Cp}$ and Cv denote the specific heat of oxygen per unit mass at constant Pressure and volume respectively, then
(A) $\mathrm{cp}-\mathrm{cv}=(\mathrm{R} / 16)$
(B) $\mathrm{Cp}-\mathrm{Cv}=\mathrm{R}$
(C) $\mathrm{Cp}-\mathrm{Cv}=32 \mathrm{R}$
(D) $\mathrm{Cp}-\mathrm{Cv}=(\mathrm{R} / 32)$