JEE Physics Practice Question

An ideal gas is in thermodynamic equilibrium. The number of degrees of freedom of a molecule of the gas is $n$. The internal energy of one mole of the gas is $U_{n}$ and the speed of sound in the gas is $\mathrm{v}_{n}$. At a fixed temperature and pressure, which of the following is the correct option?

1. A.$v_{3}<v_{6}$ and $U_{3}>U_{6}$
2. B.$v_{5}>v_{3}$ and $U_{3}>U_{5}$
3. C.$v_{5}>v_{7}$ and $U_{5}<U_{7}$
4. D.$v_{6}<v_{7}$ and $U_{6}<U_{7}$