$4.0\text{g}$ of a gas occupies $22.4$ liters at NTP. The specific heat capacity of the gas at constant volume is $5.0{\text{J K}}^{-1}{\text{mol}}^{-1}$. If the speed of sound in this gas at NTP is $952{\text{m s}}^{-1}$, then the molar heat capacity at constant pressure is (Take gas constant $R=8.3{\text{J K}}^{-1}{\text{mol}}^{-1}$):

1. A
   $8.5{\text{J K}}^{-1}{\text{mol}}^{-1}$
2. B
   $8.0{\text{J K}}^{-1}{\text{mol}}^{-1}$
3. C
   $7.5{\text{J K}}^{-1}{\text{mol}}^{-1}$
4. D
   $7.0{\text{J K}}^{-1}{\text{mol}}^{-1}$