Two closed bulbs of equal volume $(V)$ containing an ideal gas initially at pressure pi and temperature $T_1$ are connected through a narrow tube of negligible volume as shown in the figure below. The temperature of one of the bulbs is then raised to $T_2$ . The final pressure $p_f$ is : <br>

Question

( A ) $2 p_i ( \frac{T_1T_2}{T_1 + T_2})$
( B ) $p_i ( \frac{T_1T_2}{T_1 + T_2})$
( C ) $2 p_i ( \frac{T_1}{T_1 + T_2})$
( D ) $2 p_i ( \frac{T_2}{T_1 + T_2})$