Molecules of an ideal gas are known to have three translational degrees of freedom and two rotational degrees of freedom. The gas is maintained at a temperature of $T$. The total internal energy,$U$ of a mole of this gas,and the value of $\gamma \left( = \frac{C_P}{C_V} \right)$ are given,respectively,by:

• A
  $U = \frac{5}{2} RT$ and $\gamma = \frac{6}{5}$
• B
  $U = 5 RT$ and $\gamma = \frac{7}{5}$
• C
  $U = 5 RT$ and $\gamma = \frac{6}{5}$
• D
  $U = \frac{5}{2} RT$ and $\gamma = \frac{7}{5}$