# The temperature of an open room of volume $30 \;m^3$ increased from $17^{\circ}C$ to $27^{\circ}C$ due to the sunshine. The atmospheric pressure in the room remains $1 \times 10^5 \; Pa$. If $n_i$ and $n_f$ are the number of molecules in the room before and after heating, then $n_f – n_i$ will be :
( A ) $1.38 \times 10^{23}$
( B ) $2.5 \times 10^{25}$
( C ) $-2.5 \times 10^{25}$
( D ) $-1.61 \times 10^{23}$