The density of oxygen is $1,43{\mathrm{gL}}^{-1}$ at STP. Its density at ${27}^{\circ }\mathrm{C}$ and 700 Torr would be 

Its density at ${27}^{\circ }\mathrm{C}$ and 700 Torr would be,$$\begin{gathered} {\rho }_2={\rho }_1\left(\frac{p_2}{T_2}\right)\left(\frac{T_1}{p_1}\right) \\ =\left(1.43{\mathrm{gL}}^{-1}\right)\left(\frac{700\text{ Torr }}{300\mathrm{K}}\right)\left(\frac{273\mathrm{K}}{760\text{ Torr }}\right) \\ =1.20{\mathrm{gL}}^{-1} \end{gathered}$$

Thus, option A is correct.