A sample of $\mathrm{CO}{}_2$ ($T_c=304\mathrm{K}$, $P_c=73\mathrm{atm}$) is subjected to the following conditions. In which cases can a distinct liquid phase be obtained by compression at the stated temperature?

Liquefaction by pressure alone is possible only at or below the critical temperature. $280\mathrm{K}$ and $300\mathrm{K}$ are below $304\mathrm{K}$, so a liquid forms (A and B true). At $310\mathrm{K}$ and $350\mathrm{K}$ the gas becomes a supercritical fluid without a phase boundary (C and D false).