$4g$ of $O_2$ gas has pressure $P_0$ ad temperature $T_o$ i a vessel . On keeping the Sample at $50^{\circ}\;C$ higher temperature, $1g$ gas is given ad to maintain the original pressure $P_0$ . Then $T_0=?$

Question

$(A)\; 50\;K \\ (B) \; 323\;K \\ (C)\;423\;K \\ (D)\;150\;K$